Coding methods of communicating identifiers in peer discovery in a peer-to-peer network

ABSTRACT

Systems and methodologies are described that facilitate identifying peers based upon encoded signals during peer discovery in a peer to peer network. For example, direct signaling that partitions a time-frequency resource into a number of segments can be utilized to communicate an identifier within a peer discovery interval; thus, a particular segment selected for transmission can signal a portion of the identifier, while a remainder can be signaled based upon tones communicated within the selected segment. Moreover, a subset of symbols within the resource can be reserved (e.g., unused) to enable identifying and/or correcting timing offset. Further, signaling can be effectuated over a plurality of peer discovery intervals such that partial identifiers communicated during each of the peer discovery intervals can be linked (e.g., based upon overlapping bits and/or bloom filter information).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. patent application Ser.No. ______, entitled “CODING METHODS OF COMMUNICATING IDENTIFIERS INPEER DISCOVERY IN A PEER-TO-PEER NETWORK” (Atty. Docket No. 070700U1),co-pending U.S. patent application Ser. No. ______, entitled “CODINGMETHODS OF COMMUNICATING IDENTIFIERS IN PEER DISCOVERY IN A PEER-TO-PEERNETWORK” (Atty. Docket No. 070700U3), and co-pending U.S. patentapplication Ser. No. ______, entitled “CODING METHODS OF COMMUNICATINGIDENTIFIERS IN PEER DISCOVERY IN A PEER-TO-PEER NETWORK” (Atty. DocketNo. 070700U4), which were each filed on the same day as the subjectapplication.

BACKGROUND

I. Field

The following description relates generally to wireless communications,and more particularly to identifying peers based upon encoded signalsduring peer discovery in a peer-to-peer network.

II. Background

Wireless communication systems are widely deployed to provide varioustypes of communication; for instance, voice and/or data may be providedvia such wireless communication systems. A typical wirelesscommunication system, or network, can provide multiple users access toone or more shared resources. For instance, a system may use a varietyof multiple access techniques such as Frequency Division Multiplexing(FDM), Time Division Multiplexing (TDM), Code Division Multiplexing(CDM), Orthogonal Frequency Division Multiplexing (OFDM), and others.

Common wireless communication systems employ one or more base stationsthat provide a coverage area. A typical base station can transmitmultiple data streams for broadcast, multicast and/or unicast services,wherein a data stream may be a stream of data that can be of independentreception interest to a wireless terminal. A wireless terminal withinthe coverage area of such base station can be employed to receive one,more than one, or all the data streams carried by the composite stream.Likewise, a wireless terminal can transmit data to the base station oranother wireless terminal.

Wireless communication systems leverage various portions of wirelessspectrum for transferring data. However, wireless spectrum is anexpensive and valuable resource. For example, significant costs may beincurred by a company desiring to operate a wireless communicationsystem over a portion of the wireless spectrum (e.g., within thelicensed spectrum). Further, conventional techniques typically provideinefficient utilization of wireless spectrum. According to a commonillustration, the spectrum allocated for wide area network cellularcommunication oftentimes is not uniformly utilized across time andspace; thus, a significant subset of spectrum may be unused in a givengeographic location or in a given time interval.

According to another example, wireless communication systems oftentimesemploy peer-to-peer or ad hoc architectures whereby a wireless terminalmay transfer signals directly to another wireless terminal. As such,signals need not traverse through a base station; rather, wirelessterminals within range of each other may discover and/or communicatedirectly. However, conventional peer-to-peer networks typically operatein an asynchronous manner whereby peers may effectuate differing tasksat a particular time. Consequently, peers may encounter difficultyassociated with identifying and/or communicating with disparate peerswithin range, power may be inefficiently utilized, and so forth.

SUMMARY

The following presents a simplified summary of one or more embodimentsin order to provide a basic understanding of such embodiments. Thissummary is not an extensive overview of all contemplated embodiments,and is intended to neither identify key or critical elements of allembodiments nor delineate the scope of any or all embodiments. Its solepurpose is to present some concepts of one or more embodiments in asimplified form as a prelude to the more detailed description that ispresented later.

In accordance with one or more embodiments and corresponding disclosurethereof, various aspects are described in connection with facilitatingidentification of peers based upon encoded signals during peer discoveryin a peer to peer network. For example, direct signaling that partitionsa time-frequency resource into a number of segments can be utilized tocommunicate an identifier within a peer discovery interval; thus, aparticular segment selected for transmission can signal a portion of theidentifier, while a remainder can be signaled based upon tonescommunicated within the selected segment. Moreover, a subset of symbolswithin the resource can be reserved (e.g., unused) to enable identifyingand/or correcting timing offset. Further, signaling can be effectuatedover a plurality of peer discovery intervals such that partialidentifiers communicated during each of the peer discovery intervals canbe linked (e.g., based upon overlapping bits and/or bloom filterinformation).

According to related aspects, a method that facilitates incorporatingreserved symbols within a peer discovery interval is described herein.The method can include synchronizing timing within a peer to peernetwork. Further, the method can comprise transmitting at least aportion of an identifier during a peer discovery interval as specifiedby the timing. Moreover, the method can include reserving at least onesymbol within the peer discovery interval to enable identifying andrecovering from timing offset.

Another aspect relates to a wireless communications apparatus. Thewireless communications apparatus can include a memory that retainsinstructions related to synchronizing timing within a peer to peernetwork, transmitting at least a portion of an identifier during a peerdiscovery interval as specified by the timing, and reserving at leastone symbol within the peer discovery interval to enable identifying andrecovering from timing offset. Further, the wireless communicationsapparatus can include a processor, coupled to the memory, configured toexecute the instructions retained in the memory.

Yet another aspect relates to a wireless communications apparatus thatenables incorporating reserved symbols within a peer discovery interval.The wireless communications apparatus can include means forsynchronizing timing within a peer to peer network; means fortransmitting at least a portion of an identifier during a peer discoveryinterval as specified by the timing; and means for reserving at leastone symbol within the peer discovery interval to enable identifying andrecovering from timing offset.

Still another aspect relates to a machine-readable medium having storedthereon machine-executable instructions for synchronizing timing withina peer to peer network, transmitting at least a portion of an identifierduring a peer discovery interval as specified by the timing, andreserving at least one symbol within the peer discovery interval toenable identifying and recovering from timing offset.

In accordance with another aspect, an apparatus in a wirelesscommunication system can include a processor, wherein the processor canbe configured to synchronize timing within a peer to peer network.Further, the processor can be configured to transmit at least a portionof an identifier during a peer discovery interval as specified by thetiming. Moreover, the processor can be configured to reserve at leastone symbol within the peer discovery interval to enable identifying andrecovering from timing offset.

According to other aspects, a method that facilitates shifting timing tomitigate offset within peer discovery is described herein. The methodcan include synchronizing timing within a peer to peer network. Also,the method can include receiving tones upon symbols pertaining to atleast one identifier during a peer discovery interval. Further, themethod can comprise identifying timing offset upon obtaining a tone upona reserved symbol. Moreover, the method can include correcting thetiming offset.

Yet another aspect relates to a wireless communications apparatus thatcan include a memory that retains instructions related to synchronizingtiming within a peer to peer network, receiving tones upon symbolspertaining to at least one identifier during a peer discovery interval,identifying timing offset upon obtaining a tone upon a reserved symbol,and correcting the timing offset. Moreover, the wireless communicationsapparatus can include a processor, coupled to the memory, configured toexecute the instructions retained in the memory.

Another aspect relates to a wireless communications apparatus thatenables shifting timing to mitigate offset within peer discovery. Thewireless communications apparatus can include means for synchronizingtiming within a peer to peer network; means for receiving tones uponsymbols pertaining to at least one identifier during a peer discoveryinterval; means for identifying timing offset upon obtaining a tone upona reserved symbol; and means for correcting the timing offset.

Still another aspect relates to a machine-readable medium having storedthereon machine-executable instructions for synchronizing timing withina peer to peer network, receiving tones upon symbols pertaining to atleast one identifier during a peer discovery interval, identifyingtiming offset upon obtaining a tone upon a reserved symbol, andcorrecting the timing offset.

In accordance with another aspect, an apparatus in a wirelesscommunication system can include a processor, wherein the processor canbe configured to synchronize timing within a peer to peer network and/orreceive tones upon symbols pertaining to at least one identifier duringa peer discovery interval. Moreover, the processor can be configured toidentify timing offset upon obtaining a tone upon a reserved symboland/or correct the timing offset.

To the accomplishment of the foregoing and related ends, the one or moreembodiments comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative aspects ofthe one or more embodiments. These aspects are indicative, however, ofbut a few of the various ways in which the principles of variousembodiments may be employed and the described embodiments are intendedto include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a wireless communication system inaccordance with various aspects set forth herein.

FIG. 2 is an illustration of an example system that synchronizescommunication between wireless terminals in a peer-to-peer network.

FIG. 3 is an illustration of an example timing diagram utilized bysynchronized peers communicating within a peer-to-peer environment.

FIG. 4 is an illustration of an example timing diagram of a peerdiscovery interval.

FIG. 5 is an illustration of an example system that effectuatessynchronized communications over a peer-to-peer network.

FIG. 6 is an illustration of an example time-frequency grid associatedwith transmission during a peer discovery interval.

FIG. 7 is an illustration of an example system that enables employing areversible function for generating a peer discovery signal, whereutilization of the reversible function allows identifiers to bedeciphered from received signals in a peer-to-peer network.

FIG. 8 is an illustration of an example graphical depiction of anevaluation of a linked sequence of peer discovery signals generated witha reversible function.

FIG. 9 is an illustration of an example graphical depiction of aresource utilized for a direct signaling coding scheme employed for peerdiscovery.

FIG. 10 is an illustration of an example segment selected from a peerdiscovery interval.

FIG. 11 is an illustration of an example timing offset between wirelessterminals during peer discovery.

FIG. 12 is an illustration of a graphical example depicting transfer ofpartial identifiers over a plurality of peer discovery intervals tocommunicate a complete identifier for peer discovery.

FIG. 13 is an illustration of another example graphical depiction of alinking scheme for communicating an identifier over a plurality of peerdiscovery intervals.

FIG. 14 is an illustration of an example graphical depiction of a schemethat employs a bloom filter to verify whether an identifier iscommunicated during peer discovery.

FIG. 15 is an illustration of an example graphical depiction of asliding window and a bloom filter.

FIG. 16 is an illustration of an example methodology that facilitatesdirectly signaling an identifier during peer discovery.

FIG. 17 is an illustration of an example methodology that facilitatesdecoding a directly signaled identifier during peer discovery.

FIG. 18 is an illustration of an example methodology that facilitatesincorporating reserved symbols within a peer discovery interval.

FIG. 19 is an illustration of an example methodology that facilitatesshifting timing to mitigate offset within peer discovery.

FIG. 20 is an illustration of an example methodology that facilitatessignaling an identifier over a plurality of peer discovery intervals.

FIG. 21 is an illustration of an example methodology that facilitateslinking partial identifiers obtained during differing peer discoveryintervals based upon overlapping information.

FIG. 22 is an illustration of an example methodology that facilitatesemploying a bloom filter while signaling partial identifiers for peerdiscovery.

FIG. 23 is an illustration of an example methodology that facilitatesemploying a bloom filter to match partial identifiers.

FIG. 24 is an illustration of an example communication systemimplemented in accordance with various aspects including multiple cells.

FIG. 25 is an illustration of an example base station in accordance withvarious aspects.

FIG. 26 is an illustration of an example wireless terminal (e.g., mobiledevice, end node, . . . ) implemented in accordance with various aspectsdescribed herein.

FIG. 27 is an illustration of an example system that enables directlysignaling an identifier during peer discovery.

FIG. 28 is an illustration of an example system that enables decoding adirectly signaled identifier during peer discovery.

FIG. 29 is an illustration of an example system that enablesincorporating reserved symbols within a peer discovery interval.

FIG. 30 is an illustration of an example system that enables shiftingtiming to mitigate offset within peer discovery.

FIG. 31 is an illustration of an example system that enables signalingan identifier over a plurality of peer discovery intervals.

FIG. 32 is an illustration of an example system that enables linkingpartial identifiers obtained during differing peer discovery intervalsbased upon overlapping information.

FIG. 33 is an illustration of an example system that enables employing abloom filter while signaling partial identifiers for peer discovery.

FIG. 34 is an illustration of an example system that enables employing abloom filter to match partial identifiers.

DETAILED DESCRIPTION

Various embodiments are now described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of one or more embodiments. It may be evident, however,that such embodiment(s) may be practiced without these specific details.In other instances, well-known structures and devices are shown in blockdiagram form in order to facilitate describing one or more embodiments.

As used in this application, the terms “component,” “module,” “system,”and the like are intended to refer to a computer-related entity, eitherhardware, firmware, a combination of hardware and software, software, orsoftware in execution. For example, a component may be, but is notlimited to being, a process running on a processor, a processor, anobject, an executable, a thread of execution, a program, and/or acomputer. By way of illustration, both an application running on acomputing device and the computing device can be a component. One ormore components can reside within a process and/or thread of executionand a component may be localized on one computer and/or distributedbetween two or more computers. In addition, these components can executefrom various computer readable media having various data structuresstored thereon. The components may communicate by way of local and/orremote processes such as in accordance with a signal having one or moredata packets (e.g., data from one component interacting with anothercomponent in a local system, distributed system, and/or across a networksuch as the Internet with other systems by way of the signal).

Furthermore, various embodiments are described herein in connection witha wireless terminal. A wireless terminal can also be called a system,subscriber unit, subscriber station, mobile station, mobile, mobiledevice, remote station, remote terminal, access terminal, user terminal,terminal, wireless communication device, user agent, user device, oruser equipment (UE). A wireless terminal may be a cellular telephone, acordless telephone, a Session Initiation Protocol (SIP) phone, awireless local loop (WLL) station, a personal digital assistant (PDA), ahandheld device having wireless connection capability, computing device,or other processing device connected to a wireless modem. Moreover,various embodiments are described herein in connection with a basestation. A base station may be utilized for communicating with wirelessterminal(s) and may also be referred to as an access point, Node B, orsome other terminology.

Moreover, various aspects or features described herein may beimplemented as a method, apparatus, or article of manufacture usingstandard programming and/or engineering techniques. The term “article ofmanufacture” as used herein is intended to encompass a computer programaccessible from any computer-readable device, carrier, or media. Forexample, computer-readable media can include but are not limited tomagnetic storage devices (e.g., hard disk, floppy disk, magnetic strips,etc.), optical disks (e.g., compact disk (CD), digital versatile disk(DVD), etc.), smart cards, and flash memory devices (e.g., EPROM, card,stick, key drive, etc.). Additionally, various storage media describedherein can represent one or more devices and/or other machine-readablemedia for storing information. The term “machine-readable medium” caninclude, without being limited to, wireless channels and various othermedia capable of storing, containing, and/or carrying instruction(s)and/or data.

Referring now to FIG. 1, a wireless communication system 100 isillustrated in accordance with various embodiments presented herein.System 100 may comprise one or more wireless terminals 102. Although twowireless terminals 102 are depicted, it is to be appreciated that system100 may include substantially any number of wireless terminals 102.Wireless terminals 102 can be, for example, cellular phones, smartphones, laptops, handheld communication devices, handheld computingdevices, satellite radios, global positioning systems, PDAs, and/or anyother suitable device for communicating over wireless communicationsystem 100. Wireless terminals 102 can communicate directly with eachother via a local area peer-to-peer (P2P) network (e.g., ad hocnetwork). Peer-to-peer communication may be effectuated by directlytransferring signals between wireless terminals 102; thus, the signalsneed not traverse through a base station (e.g., base station 104). Thepeer-to-peer network may provide short range, high data ratecommunication (e.g., within a home, office, etc. type setting).

Further, system 100 may support a wide area network (WAN). System 100may include a base station 104 (e.g., access point) and/or any number ofdisparate base stations (not shown) in one or more sectors that receive,transmit, repeat, etc. wireless communication signals to each otherand/or to one or more wireless terminals 102. Base station 104 cancomprise a transmitter chain and a receiver chain, each of which can inturn comprise a plurality of components associated with signaltransmission and reception (e.g., processors, modulators, multiplexers,demodulators, demultiplexers, antennas, . . . ) as will be appreciatedby one skilled in the art. Wireless terminal(s) 102 may transmit signalsto and/or receive signals from base station 104 when communicating viathe wide area infra-structure network supported by system 100.

Peer-to-peer communication between wireless terminals 102 may besynchronous. For example, wireless terminals 102 may utilize a commonclock reference to synchronize performance of distinct functions.Wireless terminals 102 may obtain timing signals from base station 104(and/or a transmitter (not shown) that provides less functionality)utilized to synchronize operation of wireless terminals 102. Wirelessterminal 102 may obtain timing signals from other sources, such as GPSsatellites. According to an illustration, time may be meaningfullypartitioned in a peer-to-peer network for functions such as peerdiscovery, paging, and traffic. Further, it is contemplated that eachpeer-to-peer network may set its own time.

Before communication in a peer-to-peer network can take place, wirelessterminals 102 (e.g., peers) may detect and identify each other. Theprocess by which this mutual detection and identification between peerstakes place may be referred to as peer discovery. System 100 may supportpeer discovery by providing that peers desiring to establishpeer-to-peer communication periodically transmit short messages andlisten to the transmissions of others.

Transmissions for peer discovery may periodically occur during specifiedtimes referred to as peer discovery intervals, the timing of which maybe predetermined by a protocol and known to wireless terminals 102.Peers may be synchronized to a common clock reference. For example,wireless terminals 102 may decode a small amount of broadcastinformation from locally positioned base station 104. Synchronizationmay allow for peers in a given geographic location to recognize a startand a finish of each discovery interval.

The local area peer-to-peer network and the wide area network may sharea common wireless spectrum to effectuate communication; thus, bandwidthmay be shared for transferring data via the disparate types of networks.For example, the peer-to-peer network and the wide area network may bothcommunicate over the licensed spectrum. However, the peer-to-peercommunication need not utilize the wide area network infrastructure.

Now turning to FIG. 2, illustrated is a system 200 that synchronizescommunication between wireless terminals in a peer-to-peer network.System 200 includes a wireless terminal 202 that communicates directlywith substantially any number of disparate wireless terminals (e.g.,disparate wireless terminal 1 204, . . . , disparate wireless terminal X206, where X may be any integer). Although the following providesfurther detail with regards to wireless terminal 202, it is to beappreciated that such illustrations may similarly apply to disparatewireless terminals 204-206.

Wireless terminal 202 may further include a synchronizer 208 thatconforms timing between wireless terminal 202 and disparate wirelessterminals 204-206. Synchronizer 208 may obtain its timing from a commonclock reference. Similar synchronizers (not shown) of disparate wirelessterminals 204-206 may obtain their respective timing from the samecommon clock reference. Further, synchronizer 208 may utilize apredetermined protocol to evaluate the common clock reference toidentify a type of function to be effectuated at the time associatedwith the common clock reference (e.g., current time). Thus, for example,synchronizer 208 and similar synchronizers (not shown) of disparatewireless terminals 204-206 may determine that a time period identifiedfrom the common clock reference may be employed for one of peerdiscovery, paging, or traffic. The time period identified will besubstantially the same or similar for synchronizer 208 and similarsynchronizers (not shown) of disparate wireless terminals 204-206, eventhough wireless terminals 202-206 have not directly communicate witheach other.

The common clock reference utilized by synchronizer 208 may be broadcastinformation from a base station (not shown) in a vicinity of wirelessterminal 202 and disparate wireless terminals 204-206. Another commonclock reference may include GPS satellite signals. For example, thebroadcast information may be a Beacon, a PN (pseudo random) sequencesignal, a pilot signal or other broadcast signal. Further, the broadcastsignal may be periodically received from the base station. Moreover,timing information may be determined from the broadcast signal bysynchronizer 208. By way of illustration, wireless terminal 202 anddisparate wireless terminals 204-206 may receive and synchronize to thesame broadcast signal, and therefore, have a common understanding oftime. The common notion of time may be utilized to partition a timelineinto distinct periods for each type of function (e.g., peer discovery,paging, traffic) according to a predetermined pattern defined by the airinterface protocol.

Additionally, wireless terminal 202 may include a peer discoverycommunicator 210 that effectuates peer discovery during a peer discoveryinterval as determined by synchronizer 208. Peer discovery communicator210 may further comprise a signal broadcaster 212 and a peer detector214. Signal broadcaster 212 may transmit a message, in a first portionof the peer discovery interval, to disparate wireless terminals 204-206that enables disparate wireless terminals 204-206 to detect and identifywireless terminal 202. Further, in a second portion of the peerdiscovery interval, peer detector 214 may receive message(s) sent fromdisparate wireless terminal(s) 204-206; peer detector 214 may analyzethe received message(s) to detect and identify disparate wirelessterminal(s) 204-206 to which the message(s) correspond. In someembodiments, the first and the second portions of the peer discoveryinterval may not overlap in time. Further, a transmit/receive switchguard time may be reserved between the first and the second portions ofthe peer discovery interval.

By way of example, wireless terminal 202 may enter into a peer-to-peernetwork that includes disparate wireless terminal 1 204 and disparatewireless terminal X 206. Upon entering the network, synchronizer 208 maydetermine timing associated with peer-to-peer communications (e.g.,based upon a received common clock reference). Further, at a timepartitioned for peer discovery, signal broadcaster 212 may broadcast asignal to disparate wireless terminals within range (e.g., disparatewireless terminals 204-206). The signal may be utilized by disparatewireless terminals 204-206 to detect that wireless terminal 202 hasentered the network and/or determine an identity of wireless terminal202. Moreover, peer detector 214 may obtain broadcast signals fromdisparate wireless terminals 204-206. Peer detector 214 may analyze theobtained signals to detect disparate wireless terminals 204-206 and/oridentify disparate wireless terminals 204-206.

Peer discovery effectuated by peer discovery communicator 210 may bepassive. Further, peer discovery may be symmetric; thus, wirelessterminal 202 may detect and identify disparate wireless terminal 1 204and disparate wireless terminal 1 204 may detect and identify wirelessterminal 202. However, it is contemplated that a first wireless terminalmay detect and identify a second wireless terminal, but the secondwireless terminal may fail to detect and identify the first wirelessterminal. Moreover, the defined time interval utilized for peerdiscovery may be much shorter than the time between peer discoveryintervals. Additionally, upon detection and identification, furthercommunication (e.g., paging, traffic) between wireless terminal 202 anddisparate wireless terminal(s) 204-206 may, but need not, beeffectuated.

Referring to FIG. 3, illustrated is an example timing diagram 300utilized by synchronized peers communicating within a peer-to-peerenvironment. Timing diagram 300 may be partitioned with intervals forpeer discovery as well as intervals for differing functions such aspaging and communicating traffic. As noted above, peers may besynchronized with one another based upon a common clock reference; thus,the peers may have a common notion of timing diagram 300. Peer discoveryintervals 302 are illustrated. Each peer discovery interval 302 may havea duration of To. Peer discovery intervals 302 may be dedicated fordetecting and identifying peers. Further, the time between peerdiscovery intervals 302 may be T₁. Any number of paging and/or trafficintervals may be included during T₁ between adjacent peer discoveryintervals 302. The terminal may transition to a sleep mode (e.g., forpower saving) during T₁ interval, for example, when the terminal doesnot find any peer in the peer discovery interval or does not find anypeer of interest.

The amount of time allocated for peer discovery may be a small fractionof the overall time. For instance, the time (T₁) between peer discoveryintervals may be at least 5 times larger than the time (T₀) allotted foreach peer discovery interval 302. Pursuant to another example, the ratioof T₁ to T₀ may be 10, 50, 100, 200, 300, and so forth. According to afurther example, peer discovery intervals 302 may have a duration, T₀,on the order of 2 ms (e.g., around 10 ms, 50 ms, . . . ). By way offurther illustration, T₁, the time between peer discovery intervals, maybe on the order of a few seconds or 1 minute. Allocating a small portionof overall time for peer discovery provides efficient utilization ofpower, since peers not involved in communicating pages and/or trafficmay sleep during the time, T₁, in between each peer discovery interval302.

With reference to FIG. 4, illustrated is an example timing diagram 400of a peer discovery interval. The peer discovery interval may include anumber of possible transmission times during which a wireless terminalcan broadcast a signal. For instance, the peer discovery interval mayinclude N symbols (e.g., OFDM symbols), where N may be any integer.Further, each symbol may last 10μs and N may be 50, 100, 200, etc.;however, the subject claims are not so limited. Each peer within apeer-to-peer network may transmit utilizing one or more of the symbols;the peer may listen to the remainder of the symbols to detect and/oridentify other peers within range. In accordance with an example, a peermay transmit on a first symbol at a first time and a second symbol at asecond time, where the first time and the second time may or may not becontiguous.

According to an example, the peer discovery interval may include 200symbols. In one or more embodiments, the 200 symbols may be used fortransmitting broadcast signals by the terminals. In other embodiments,every other symbol may be utilized for transmission (e.g., 100 symbolsmay be employed for transmission). Before the peer discovery interval,each wireless terminal that wishes to engage in peer-to-peercommunication may select one or more transmission symbols (e.g., out ofthe total of 100 transmission symbols pursuant to the above example).During the selected symbol time(s), the wireless terminal transmits amessage to disparate wireless terminal(s) (e.g., peer(s)). The messagemay include one tone in one of the selected transmission symbols.Further, during at least a fraction of the remaining symbol times in thepeer discovery interval, the wireless terminal listens and decodes thetransmissions of the disparate wireless terminal(s). Since peer-to-peercommunication may employ a half-duplex mode, where a wireless terminaleither transmits or receives data at a particular time, the wirelessterminal may transmit for 10% of the transmission times and receive forthe remaining 90% of the time. By way of another example, the wirelessterminal may transmit 30% of the time and receive 70% of the time. Inaccordance with an illustration, the wireless terminal may determine thetransmission time(s) and/or the waveform (e.g., the frequency tonetransmitted in a selected transmission symbol) to transmit based upon anidentifier and/or a notion of time (e.g., derived from a receivedBeacon). The notion of time is in essence a time-varying variable. Allthe wireless terminals may get the same notion of time. For example, thewireless terminals may obtain a time-varying variable from the broadcast(e.g., beacon) signal from the base station. The time-varying variablecan be some variable transmitted in the broadcast signal. For example,the variable can be some time counter or system time, which varies overtime. In this document, the notion of time is referred to as timecounter. It is desired that the time counter varies from one peerdiscovery interval to another. By way of further example, the wirelessterminal may utilize a pseudo-random number generator, whose seed can bean identifier of the wireless terminal and a current counter valuesupplied by a broadcast signal from a base station, to selecttransmission time(s) and/or the waveform. As the time counter varies,the selected transmission symbol time(s) and/or waveform may also varyfrom one peer discovery interval to another.

Referring now to FIG. 5, illustrated is a system 500 that effectuatessynchronized communications over a peer-to-peer network. System 500includes wireless terminal 202 that may communicate via a peer-to-peernetwork with disparate wireless terminal(s) (e.g., peer(s)). Wirelessterminal 202 may include synchronizer 208 that coordinates performanceof various functions (e.g., peer discovery, paging, traffic).Synchronizer 208 may obtain and analyze a common clock reference todetermine a meaningful notion of time. Additionally, the disparatewireless terminal(s) may obtain and analyze the common clock referenceto yield the same notion of time; hence, peers within a local area maysynchronize with the same common clock reference (e.g., from the samebase station). Therefore, peers get the same timing (timingsynchronized) without directly communicating with each other. Forexample, the common clock reference may be a Beacon signal transmittedby a base station within range of wireless terminal 202 and the peers.Further, wireless terminal 202 may comprise peer discovery communicator210, which further includes signal broadcaster 212 and peer detector214.

Peer discovery communicator 210 may also include a signal generator 502that yields a message to be sent by signal broadcaster 212. According toan example, signal generator 502 may determine transmission time(s)within a peer discovery interval and/or waveform(s) to be transmitted.Signal generator 502 may yield transmission time(s) and/or waveform(s)of the message as a function of an identifier (ID) (e.g., correspondingto wireless terminal 202) and a time (e.g., determined from common clockreference). In accordance with an example, the message yielded by signalgenerator 502 may be a Beacon signal, which may provide powerefficiency; thus, signal generator 502 may effectuate transmitting aparticular tone on a selected OFDM symbol. It is contemplated that morethan one Beacon signal may be transmitted. Further, due to privacyissues, safeguards may be put into place to mitigate undesireddistribution of the ID of wireless terminal 202.

Pursuant to another example, signal generator 502 may provide signalbroadcaster 212 with an ID associated with wireless terminal 202 thatmay be broadcast to peer(s). Peer(s) obtaining the ID may detect andidentify wireless terminal 202 by utilizing the received ID. Forexample, the ID of wireless terminal 202 may be an output of an M-bithash function whose input is the plain-text name of wireless terminal202 and a current counter value supplied by a base station broadcastsignal (e.g., common clock reference, Beacon, . . . ). The countervalue, for instance, may be constant during a current peer discoveryinterval and may be decodable by all peers. Further, the hash functionmay be specified a priori by a protocol and known to the peers.

By way of an example, peer detector 214 may maintain a list ofplain-text names of buddy peers associated with wireless terminal 202.Further, upon decoding a particular ID, peer detector 214 may hash itsplain-text buddy names using the current counter value. If at least oneof the output IDs matches the decoded ID, peer detector 214 may concludethat the corresponding buddy peer is present. If no match is found orthere are multiple matches, peer detector 214 may be unable to concludeas to the presence of any buddy peers. Moreover, each peer may vary thenumber of bits, previously denoted by M, of the output of the IDgenerating hash function in order to ensure that it is eventuallydiscovered. A peer maintains a list of disparate wireless terminals thatare detected to be present in the current time. The list may include alldisparate wireless terminals or may include those in the predefinedbuddy list of wireless terminal 202 or the user who is using wirelessterminal 202. As the time goes by, the list evolves, because somedisparate wireless terminals may disappear (e.g., because thecorresponding users move away), or because other disparate wirelessterminals may appear (e.g., because the corresponding users move close).The peer may add the new disparate wireless terminals to the list ordelete disappearing disparate wireless terminals from the list. In anembodiment, the peer passively maintains the list. In this case, a firstpeer may detect the presence of a second peer and keep the second peerin its list without informing the second peer. As a result, the secondpeer may not know that the first peer has already kept the second peerin the list. By symmetry, depending on wireless channel and interferencecondition, the second peer may also detect the presence of the firstpeer and keep the first peer in its list without informing the firstpeer. In another embodiment, after the first peer detects the presenceof the second peer, the first peer proactively sends a signal to informthe second peer so that the second peer now knows that the first peerhas already kept the second peer in the list, even though the first peerhas no data traffic to communicate with the second peer yet. The firstpeer may selectively decide whether it sends a signal. For example, thefirst peer may send a signal only to another peer that is in thepredefined buddy list.

Wireless terminal 202 may also include a pager 504 and a trafficcommunicator 506. Based upon the synchronized notion of time yielded bysynchronizer 208, pager 504 and traffic communicator 506 may transmitand/or receive signals via the peer-to-peer network during respective,allocated times for such functions. Upon detecting and identifying apeer, pager 504 enables wireless terminal 202 to initiate communicationwith the peer. Further, during an allotted traffic interval, wirelessterminal 202 and the peer may transmit and/or receive traffic byemploying traffic communicator 506.

Wireless terminal 202 may additionally include a state transitioner 508.To provide power savings, state transitioner 508 may enable wirelessterminal 202 to enter a sleep state during time intervals associatedwith functions (e.g., paging, traffic) other than peer discovery whenwireless terminal 202 is not involved with such functions. Further,state transitioner 508 switches wireless terminal 202 to an on state(e.g., from a sleep state) during peer discovery intervals to enablewireless terminal 202 to discover peer(s) and/or be discovered bypeer(s).

Moreover, wireless terminal 202 may include memory 510 and a processor512. Memory 510 may retain an identifier associated with wirelessterminal 202. Further, memory 510 may include a list a buddy peers thatmay be referenced by peer detector 214. Additionally, memory 510 mayretain instructions related to synchronizing time intervals fordiffering functions with disparate wireless terminals, establishing acommon period of time for peer discovery in a local area (e.g., basedupon information obtained from a base station), identifying location(s)within a peer discovery interval for broadcasting wireless terminalrelated signals, generating signals for transmission to disparatewireless terminals, detecting and/or identifying disparate wirelessterminals within range, and so forth. Moreover, processor 512 mayexecute instructions described herein.

Referring to FIG. 6, illustrated is an example time-frequency grid 600associated with transmission during a peer discovery interval. Thex-axis represents time and may include N symbols (e.g., where N may beany integer), and the y-axis represents frequency and may include Mtones (e.g., where M may be any integer). According to an example, awireless terminal may select a particular symbol (e.g., transmissiontime) for transmission (e.g., based upon an identifier of the wirelessterminal or the user who is using the wireless terminal and/or timecounter). Further, a particular tone corresponding to the selectedsymbol may be determined (e.g., based upon the identifier and/or time).Thus, the x and y coordinates (e.g., (x₁, y₁)) within grid 600, asillustrated by the shading, may provide information (e.g., whenevaluated by a peer receiving such signal). By transmitting a singlesymbol, the alphabet employed by the wireless terminal may be log₂(M·N).According to a further example, more than one symbol may be utilized bythe wireless terminal for transmission during the peer discoveryinterval. Pursuant to this example, the tones (e.g., Beacons) may betransmitted at different times. By way of illustration, if two Beaconsare transmitted with coordinates (x₁, y₁) and (x₂, y₂), x₁ differs fromx₂ to mitigate transmitting the two Beacons concurrently.

Now turning to FIG. 7, illustrated is a system 700 that enablesemploying a reversible function for generating a peer discovery signal,where utilization of the reversible function allows identifiers to bedeciphered from received signals in a peer-to-peer network. System 700includes wireless terminal 202 that communicates via the peer-to-peernetwork with disparate wireless terminal(s). Wireless terminal 202 mayinclude synchronizer 208, peer discovery communicator 210 and memory510.

Peer discovery communicator 210 (and similar peer discoverycommunicator(s) of disparate wireless terminal(s)) may utilize areversible function for encoding and/or evaluating signals communicatedover the peer-to-peer environment. As such, wireless terminal 202 anddisparate wireless terminal(s) may abide by a function (e.g., hashfunction) so that their unique identifiers can be discerned in one peerdiscovery interval or across a series of peer discovery intervals.Signal generator 502 may employ the reversible function to yield a peerdiscovery signal based on an identifier of wireless terminal 202 and atime counter, and the signal may be provided to disparate wirelessterminal(s) within the peer-to-peer network (e.g., via broadcast). Byleveraging the reversible function, the identifier (WT ID) may bedeciphered by disparate wireless terminal(s) that detect the peerdiscovery signal transmitted by wireless terminal 202. For example, thereversible function may be a linear function or a non-linear function.Moreover, signal broadcaster 212 may transmit the peer discovery signalyielded by signal generator 502.

Signal generator 502 may include an encoding sequence linker 702 thatlinks signal formats in successive peer discovery intervals based upon afixed and predetermined rule (e.g., reversible function). According toan example, the identifier (WT ID) may include 32 bits or more; however,a beacon signal communicated in a peer discovery interval with 200symbols and 50 tones provides 10 bits. Thus, encoding sequence linker702 may enable communicating the identifier by providing portions of theidentifier via signals sent in more than one peer discovery interval.Encoding sequence linker 702 utilizes the reversible function to enablethe identifier to be recognized over R peer discovery intervals, where Rmay be any integer (e.g., less than 3, 3, less than 20, . . . ). Forexample, encoding sequence linker 702 may enable sending a first beaconduring a first peer discovery interval, a second beacon during a secondpeer discovery interval, and so forth, where the beacons may be linkedaccording to the reversible function.

Moreover, peer detector 214 may include a signal detector 704, adecoding sequence linker 706, and an identifier discerner 708. Signaldetector 704 may obtain signal(s) communicated over the peer-to-peernetwork during peer discovery intervals. For instance, signal(s) may begenerated by disparate wireless terminal(s) (e.g., that employ thereversible function to generate such signals) and/or may correspond tonoise or interference. According to an example, signal detector 704 mayidentify coordinate pairs of symbol(s) and corresponding tone(s) relatedto the detected signals. Decoding sequence linker 706 may utilize thefixed and predetermined rule to link together signal(s) from successivepeer discovery intervals. Further, decoding sequence linker 706 mayleverage knowledge of the function employed by an encoding sequencelinker of a disparate wireless terminal to identify a sequence ofsignals from differing peer discovery intervals that correspond to oneanother. Moreover, identifier discerner 708 may evaluate the sequence ofsignals to determine the identifier encoded upon such signals. Forinstance, a list of identified disparate wireless terminals may beupdated according to the analysis effectuated by identifier discerner708.

By leveraging a reversible function, system 700 enables identifyingdisparate wireless terminals in a peer-to-peer network whether or notwireless terminal 202 has prior knowledge of identifiers related to thedisparate wireless terminals (and similarly wireless terminal 202 may beidentified by disparate wireless terminal(s)). Such recognition ofwireless terminal(s) located within range may enhance coordination oftraffic transmission and management of interference among multiplepeer-to-peer connections.

According to an illustration, the identifier of wireless terminal 202(e.g., WT ID retained in memory 510 of wireless terminal 202) may bediscoverable from signals transmitted by signal generator 502 ofwireless terminal 202. Likewise, unique identifiers respectivelycorresponding to disparate wireless terminals in the peer-to-peernetwork may be similarly discoverable (e.g., by peer detector 214 ofwireless terminal 202). Further, based upon the determinedidentifier(s), peer detectors (e.g., peer detector 214) may recognizeanother wireless terminal as a peer. For example, the signal formatstransmitted in successive peer discovery intervals may be linked witheach other with a fixed and predetermined rule (e.g., by encodingsequence linkers of wireless terminals), which is applicable across thepeer-to-peer network. During a particular peer discovery interval,multiple wireless terminals may transmit their signature signals.However, a signature signal in one peer discovery interval may notuniquely identify a transmitting wireless terminal (e.g., wirelessterminal 202, disparate wireless terminal(s)). Thus, the transmittingwireless terminal may form a sequence of signature signals transmittedby that single transmitting wireless terminal over successive peerdiscovery intervals in order to recover the identifier of thetransmitting wireless terminal. Moreover, the fixed and predeterminedrule helps a receiving wireless terminal (e.g., wireless terminal 202,disparate wireless terminal(s)) form one sequence of the signaturesignals so as to construct the identifier of the transmitting wirelessterminal.

Substantially any fixed and predetermined rule may be employed whenusing beacon signals. Pursuant to an example, the signature signals fromone transmitting wireless terminal may have the same position of theselected OFDM symbol in successive intervals. The transmitting wirelessterminal may choose to skip a subset of the time intervals fortransmission so that it can monitor those time intervals and checkwhether other transmitting wireless terminals are sending signaturesignals in those time intervals. In another example, the signaturesignals from one transmitting wireless terminal have the same positionof the selected tone in successive time intervals. The positions of theselected symbols may be a function of the identifier of the transmittingwireless terminal. In yet another example, in two successive timeintervals, the signature signals from one transmitting wireless terminalmay be sent at tone y₁ of selected symbol x₁ and at tone y₂ of selectedsymbol x₂, respectively; according to this example, the rule may be thaty₂=x₁ or x₂=y₁. It is understood that the above equation may be definedin a modulo sense, where the modulus is a predetermined constant. Ingeneral, the linking function represents a constraint that xi, y₁, x₂,y₂ have to satisfy, that is g(x₁, y₁, x₂, y₂)=0.

With reference to FIG. 8, illustrated is an example graphical depictionof an evaluation of a linked sequence of peer discovery signalsgenerated with a reversible function. Time-frequency resource 800represents a signal (e.g., beacon) generated and/or obtained during afirst peer discovery interval, T_(i), and time-frequency resource 802represents a signal generated and/or obtained during a second peerdiscovery interval, T_(i+1). Moreover, the first peer discoveryinterval, T_(i), may be the peer discovery interval proceeding thesecond peer discovery interval, T_(i+1). The time-frequency resources800-802 may be similar to time-frequency resource 600 of FIG. 6.Further, it is to be appreciated, however, that the claimed subjectmatter is not limited to these examples.

According to the depicted example, the reversible function may provideinformation related to the identifier based upon the selected symbol(e.g., x axis). Further, information utilized to link signals fromsuccessive peer discovery intervals may be provided by the selected tone(e.g., y axis). For example, the reversible function may provide thaty_(i+1)=x_(i). By way of illustration, a signal may be transmittedduring the first peer discovery interval, T_(i), with a coordinate pair(x_(i), y_(i)). The selected symbol, x_(i), may provide informationassociated with a part of the identifier, while the remainder may beincluded in subsequent signal(s) that may be linked in a sequence. Todetermine the signal within the next peer discovery interval, T_(i+1),that is included in the sequence, the signal with a selected tonecoordinate, y_(i+1), that is equal to x_(i) is identified. Further,although not shown, during a following peer discovery interval, T_(i+2),y_(i+2)=x_(i+1), and so forth. Although one signal is illustrated duringeach peer discovery interval, it is contemplated that any number ofsignals may be transmitted and/or received during each such interval.Additionally, it is to be appreciated that any disparate manner oflinking beacon signals between differing peer discovery intervals isintended to fall within the scope of the hereto appended claims.Further, signals from any number of successive peer discovery intervalsmay be linked to communicate an identifier (e.g., 2, 3, 4, . . .).

Turning to FIG. 9, illustrated is an example graphical depiction of aresource 900 utilized for a direct signaling coding scheme employed forpeer discovery. Resource 900 may include N symbols and M tones, where Nand M may be substantially any integers. For example, resource 900 maybe 64 by 64; however, the claimed subject matter is not so limited.Moreover, resource 900 may be associated with a particular peerdiscovery interval, and a substantially similar resource may beassociated with a next peer discovery interval, etc. Resource 900 can beleveraged by a wireless terminal to transmit a unique ID to disparatewireless terminals as well as listen for IDs from disparate wirelessterminals.

The full ID of each wireless terminal can be 32 bits long. A wirelessterminal can form a 45 bit coded ID from the unique, raw 32 bit ID byadding another 13 bits. From one peer discovery interval to a next peerdiscovery interval, the 13 bits can change (e.g., function of time)while the 32 ID bits can remain constant. It is contemplated, forinstance, that a portion of the 13 bits can change over time, while aremainder of the 13 bits can be constant; however, the claimed subjectmatter is not so limited. For example, 10 time-independent parity checkbits can be appended to the ID along with an additional 3 time-dependentparity check bits. Moreover, the 13 bits can be generated insubstantially any manner. The coded ID (e.g., combining the 32 bits andthe 13 bits) can be denoted x. By way of illustration, the 45 bit codedID can be a concatenation of seven 6 bit symbols, x₁, x₂, x₃, x₄, x₅,x₆, and x₇, and one time dependent 3 bit symbol, x₈(t) (e.g., x(t) =[x₁x₂ x₃ x₄ x₅ x₆ x₇ x₈(t)])

Further, resource 900 of the peer discovery slot can be divided into Ksegments, where K can be substantially any integer; thus, resource 900can be partitioned into K subgroups. According to an example whereresource 900 is a 64 by 64 time-frequency grid (e.g., 64 tones and 64symbols), resource 900 can be divided into eight segments, where each ofthe segments includes 8 symbols (e.g., and the 64 tones thatrespectively correspond to the 8 symbols). Although the followingdiscusses the aforementioned example, it is to be appreciated that theclaimed subject matter is not so limited. During a peer discoverysession at time t, the wireless terminal can select one of the eightsegments during which to transmit according to x₈(t) (e.g., whichincludes 3 group selector bits that uniquely determine one of the eightsegments of resource 900 to employ for coded ID transmission). Thus, thewireless terminal transmits during one of the eight segments and listensduring the remaining seven segments of a particular peer discoveryinterval (e.g., due to the half duplex nature of peer discovery) at timet. Moreover, since x₈(t) is time dependent, the segment employed by thewireless terminal varies with time (e.g., a wireless terminal cantransmit via a first segment during a first peer discovery interval anda second segment during a second peer discovery interval, where thefirst and second segments can be the same or different). For each columnin the selected segment, the wireless terminal can transmit at maximumpower on the time-frequency points corresponding to the associated 6 bitsymbols; thus, the j th column of a segment is used to convey the symbolx_(j) from the coded ID x (e.g., where j is between 1 and 7). Further,the eighth symbol in each segment can be a reserved (e.g., unused)symbol to provide a gap between segments (as shown by the shading)(e.g., all tones associated with the reserved symbol can be unused);according to another example, however, it is contemplated that any othersymbol within each segment can be the reserved symbol, a plurality ofsymbols in each segment can be reserved (e.g., odd or even symbols canbe reserved), and so forth.

According to an illustration, wireless terminals may not be completelysynchronous with one another. For instance, timing estimations candiffer between wireless terminals (e.g., based upon the common clockreference). According to another example, an offset in timing associatedwith disparate wireless terminals can result from the disparate wirelessterminals synchronizing within differing base stations, and therefore,having slightly different notions of time. The offset, for instance, canbe less than an amount of time associated with a symbol; however, theclaimed subject matter is not so limited. Thus, the reserved symbol (orreserved symbol(s)) can be employed to resolve this timing ambiguity.

Referring now to FIG. 10, illustrated is an example segment 1000selected from a peer discovery interval (e.g., from resource 900 of FIG.9) for transmission of an identifier according to a direct signalingcoding scheme during peer discovery. Segment 1000 can include 8 symbolsand 64 tones; however, the claimed subject matter is not so limited.Further, segment 1000 can include a reserved symbol 1002 (e.g., or aplurality of reserved symbols (not shown)). Moreover, a tone can betransmitted for each of the seven non-reserved symbols in segment 1000as depicted. Since one out of 64 tones for each symbol can be selected,transmission of a single tone on each symbol can provide 6 bits ofinformation (e.g., each related to the symbol x_(j) from the coded IDx). Thus, the first 42 bits of the 45 bit coded ID can be conveyed usingseven 6 bit symbols. Further, the last 3 bits can be conveyed via thechoice of segment 1000 from a set of segments (e.g., from the 8 segmentsincluded in resource 900). The wireless terminal that transmits duringsegment 1000 can additionally listen for ID(s) transferred by disparatewireless terminals during the remaining segments (e.g., during theremaining seven segments of resource 900) other than segment 1000associated with a peer discovery interval. Moreover, selection ofsegment 1000 from the set of segments can vary over time (e.g., during adifferent peer discovery interval, a differing segment from resource 900can be utilized for transmitting the ID).

Coding for direct signaling can be effectuated upon obtaining and/orgenerating the coded ID, which can include 32 ID bits and 13 additionalbits. It is contemplated that the coded ID or a portion thereof can betime varying (e.g., a portion of the coded ID for a particular wirelessterminal can differ between peer discovery intervals). Moreover, thecoded ID can be split into two portions: a first portion of the coded IDcan enable selecting a segment from a set of segments to employ fortransferring data (e.g., a resource can be partitioned into the set ofsegments) and the second portion of the coded ID can relate to the seven6 bit symbols to be generated and/or sent during the selected segment.According to an example, the first portion of the coded ID that relatesto the selected segment can signal 3 bits, while the second portion cansignal the remaining 42 bits. Moreover, it is contemplated that the 42bits can be signaled in any manner within the selected segment (e.g.,employing phase-shift keying (PSK), differential phase-shift keying(DPSK), quadrature phase-shift keying (QPSK), quadrature amplitudemodulation (QAM), . . . ), and the claimed subject matter is not limitedto signaling via utilizing the seven 6 bit symbols as described herein.

Decoding can be performed as follows. For each segment and each column,a tone with the most energy can be identified. Thus, the identifiedtones for the seven symbols in the segment can be concatenated and thesegment symbol x₈(t) can be appended to form an estimate of x(t).Thereafter, parity checks can be performed utilized a subset or all ofthe 13 bits added to the 32 ID bits. If the parity checks pass, the 13added bits can be removed and the remaining 32 bit ID can be included ina peer discovery list. If one or more of the parity checks fail,however, the ID can be discarded. Next, for each segment and eachcolumn, the tone with the second greatest energy can be identified. Thesecond highest energy tones can be concatenated as described above andthe corresponding 32 bit ID can be added to the peer discovery list ofall parity checks are passed. Additional rounds (e.g., third highestenergy, fourth highest energy, . . . ) can be performed as well. Theprobability of adding a false ID to the peer discovery list in eachdiscovery slot can be roughly 2⁻¹⁰x [number of rounds]. According toanother example, it is contemplated that the power obtained from acommon transmitting wireless terminal can have some correlation; hence,tone power should not exhibit significant variation, else a tone uponone symbol that varies to a large degree from tones upon other symbolscan be discarded (e.g., if these tones are determined to have thehighest energy, second highest energy, . . . ).

This peer discovery technique can initially identify the strongestpeers, while later, due to the random nature of segment selection, moredistant peers can be identified. Moreover, decoding performance can beimproved while increasing computational complexity. Rather thanidentifying only the maximum energy tones, for each column the two toneswith the most energy can be identified. This can create 2⁷ potentialIDs. For each ID, the parity bits can be checked. If all parity checkspass, then the ID can be added to the peer discovery list, and if anyfail the ID can be discarded. This improved decoding technique can onaverage discover more peers as compared to the aforementioned decodingtechnique. The probability of adding a false ID employing this decodingtechnique can be roughly 2⁻³.

With reference to FIG. 11, illustrated is a graphical representation oftiming offset between wireless terminals during peer discovery.According to the depicted illustration, wireless terminal A and wirelessterminal B can exhibit timing offset (e.g., between a timing 1100 ofwireless terminal A and a timing 1102 of wireless terminal B). Forinstance, the timing offset can result from each of the wirelessterminals synchronizing with disparate base stations or variations intiming estimations yielded by each of the wireless terminals based upona common clock reference; however, the claimed subject matter is not solimited. As shown, timing 1100 of wireless terminal A can be shiftedahead of timing 1102 of wireless terminal; however, it is to beappreciated that timing 1100 can lag behind and/or can be synchronizedwith timing 1102.

Any number of reserved (e.g., unused) symbols can be employed by thewireless terminals during a peer discovery interval. The reservedsymbols can be nulls. As described above, a peer discovery interval canbe partitioned into any number (e.g., eight) of segments, and each ofthe segments can include a reserved symbol; yet, it is to be appreciatedthat each of the segments can include a plurality of reserved symbols.In the depicted example, even numbered symbols can be reserved symbols(as shown by the shading) and odd numbered symbols can be utilized tocommunicate identifier related information.

According to the example shown, wireless terminal A can transmit asignal (e.g., a tone) on symbol 3 (e.g., as specified by a notion oftime of wireless terminal A set forth by timing 1100), and wirelessterminal B can receive the signal. Since the tone location and thecorresponding time index (e.g., symbol) for a transferred signal enablethe receiving wireless terminal to decode the ID of the transmittingwireless terminal, differences between the wireless terminals notions oftime can detrimentally impact performance. By way of furtherillustration, wireless terminal B can determine a time index associatedwith the transferred signal. Since an offset can exist between timing1100 of wireless terminal A and timing 1102 of wireless terminal B(e.g., wireless terminal A can have a differing time notion fromwireless terminal B), wireless terminal B can receive the signalpartially during symbol 2 and the remainder during symbol 3, yet symbol2 can be a reserved symbol in this illustrated example. Since the signalcan be partially received at wireless terminal B during such a reservedsymbol, wireless terminal B can determine that the transmitting wirelessterminal (e.g., wireless terminal A) has a different timing fromwireless terminal B. Moreover, wireless terminal B can recover from thedifference in timing by adjusting timing 1102 to mitigate suchmisalignment between timing 1100 and timing 1102. For example, wirelessterminal B can quantize the signal received over symbols 2 and 3 asbeing associated with symbol 3. Moreover, while performing thequantization, wireless terminal B can employ a parity check to evaluatewhether the received signal should be quantized to symbol 3 (or anydisparate symbol). Accordingly, utilization of the reserved symbols canmitigate an impact associated with timing ambiguity since inserted spacecan be used to detect timing offset and/or recover from the timingoffset.

In accordance with the example where a segment can include one reservedsymbol and seven symbols for communicating ID information, the reservedsymbol can enable adjusting timing of the seven symbols at the receivingwireless terminal. Thus, if the receiving wireless terminal detects thata received symbol starts and/or ends during the reserved symbol of thesegment, the seven symbols can be shifted to recover from the symboloffset. Accordingly, the receiving wireless terminal can employ thereserved symbol to determine an appropriate shift to apply to obtainedsignals to account for offset, and thereby allow for deciphering theidentifier of the transmitting wireless terminal during peer discovery.Moreover, it is to be appreciated that any ratio of reserved symbols tonon-reserved symbols can be employed, and the reserved symbols canenable detecting and/or recovering from timing offset.

Turning to FIG. 12, illustrated is a graphical example 1200 depictingtransfer of partial identifiers over a plurality of peer discoveryintervals to communicate a complete identifier for peer discovery.Pursuant to an illustration, an identifier (e.g., with or without paritybits) of a wireless terminal can be larger than an available amount ofspace associated with a resource of a peer discovery interval, and thus,more than one peer discovery interval can be utilized to signal portionsof the identifier (e.g., any number of partial identifiers). Followingthis illustration, 32 bits can be reserved for communicating theidentifier of a wireless terminal, yet the identifier can be larger than32 bits (e.g., all bits of the complete identifier are unable to fitinto the limited space). According to another example, wirelessterminals can have multiple identifiers (e.g., related to work life,social life, virtual life, etc. of users of the wireless terminals).Moreover, these multiple identifiers can be transmitted one at a time,hashed into a common identifier, etc., and accordingly, a number of bitsgreater than a size of available space provided by a resource of a peerdiscovery interval can be transferred.

A receiving wireless terminal can observe partial identifiers during twopeer discovery intervals pursuant to the illustrated example; however,it is to be appreciated that the claimed subject matter is not solimited as identifiers can be communicated over any number of peerdiscovery intervals. During peer discovery interval A 1202, any numberof partial identifiers (e.g., A₁, A₂, A₃, . . . ) can be obtained.Moreover, during peer discovery interval B 1204, any number of partialidentifiers (e.g., B₁, B₂, B₃, . . . ) can be obtained. Peer discoveryinterval A 1202 and peer discovery interval 1204 can be adjacent to oneanother in time. It is contemplated that the number of partialidentifiers observed in peer discovery interval A 1202 can be the sameand/or different from the number of partial identifiers observed in peerdiscovery interval B 1204. However, determining correspondence at thereceiving wireless terminal between a first partial identifiercommunicated during peer discovery interval A 1202 and a second partialidentifier communicated during peer discovery interval B 1204 can bedifficult at best employing conventional techniques. For example,partial identifier A₁ and partial identifier B₃ can be related such thata common source (e.g., transmitting wireless terminal) generated and/orsignaled such information; however, while employing traditionaltechniques, the receiving wireless terminal can be unable to deciphersuch correlation (e.g., link) there between. According to anillustration, coding set forth in relation to FIG. 8 can be employed tolink information between peer discovery intervals; however, the claimedsubject matter is not so limited.

Referring to FIG. 13, illustrated is another example graphical depictionof a linking scheme 1300 for communicating an identifier over aplurality of peer discovery intervals. The identifier can include Nbits, where N can be any integer. For example, the identifier can be acoded ID, a raw ID, a plurality of identifiers, a hash value associatedwith a plurality of identifiers, and so forth. The N bit identifier canbe signaled as a sequence of partial identifiers over a series of anynumber of peer discovery intervals (e.g., peer discovery interval A,peer discovery interval B, peer discovery interval C, . . . ) such thata receiving wireless terminal can obtain, reassemble and/or decode thesequence of partial identifiers to determine the identifier there from.

According to this example, a first 10 bits of the identifier can besignaled in a first peer discovery interval (e.g., peer discoveryinterval A); although this example describes signaling 10 bits duringeach peer discovery interval, it is contemplated that any number of bitsother than 10 can be communicated during each peer discovery interval.Further, for instance, any type of mapping scheme can be employed tocommunicate the 10 bits transferred during peer discovery interval A(and any of the subsequent peer discovery intervals). During a next(e.g., second) peer discovery interval (e.g., peer discovery intervalB), 10 bits of the identifier can be signaled. A subset of the 10 bitssignaled during the second peer discovery interval can overlap with aportion of the first 10 bits signaled during the first peer discoveryinterval. For example, a first 5 bits signaled during the second peerdiscovery interval can match the last 5 bits signaled during the firstpeer discovery interval; however, it is contemplated that any amount ofoverlap between peer discovery intervals can be employed. For instance,any type of linear constraint (e.g., any number of bits of a partialidentifier can overlap with bits from a previous and/or subsequentpartial identifier) can be employed when generating the partialidentifiers to enable the receiving wireless terminal to understand howto reassemble the partial identifiers communicated over a plurality ofpeer discovery intervals to recreate the identifier. Thereafter, duringa third peer discovery interval (e.g., peer discovery interval C), 10bits of the identifier can be signaled, where a subset of the 10 bits(e.g., 5 bits) can overlap with bits included in peer discovery intervalB. Moreover, any number of partial identifiers can be signaledthereafter in any number of peer discovery intervals to enablecommunicating the set of bits included in the identifier.

Turning to FIG. 14, illustrated is an example graphical depiction of ascheme 1400 that employs a bloom filter to verify whether an identifieris communicated during peer discovery. The bloom filter can be employedto determine whether the identifier is transmitted or not. According toan illustration, a transmitting wireless terminal can input itsidentifier into the bloom filter to yield a corresponding sequence(e.g., of ones and zeros); in particular, location(s) of ones in thesequence can be checked at a receiving wireless terminal to determinewith a certain probability that such identifier was transmitted. Inparticular, the bloom filter can be employed to enable linking partialidentifiers.

As illustrated, a first partial identifier can be transferred duringpeer discovery interval A and a second partial identifier can betransferred during a next peer discovery interval B; also, any number ofadditional partial identifiers can be communicated during subsequentpeer discovery intervals. For instance, the first partial identifier caninclude 10 bits and the second partial identifier can include another 10bits; yet, it is contemplated that the partial identifiers can includeany number of bits as the claimed subject matter is not so limited. Thepartial identifiers can overlap such that X bits of the first partialidentifier are to match X bits of the second partial identifier;however, it is contemplated that the partial identifiers can benon-overlapping (e.g., the first partial identifier includes a first 10bits of an identifier and the second partial identifier includes thenext 10 bits of the identifier).

Additionally, bloom filter information can be signaled along with thepartial identifier during each peer discovery interval. For instance,check B can relate to the partial identifier communicated during peerdiscovery interval B (e.g., data B) as well as the partial identifiercommunicated during the previous peer discovery interval (e.g., data Asignaled during peer discovery interval A). Thus, the combination ofthese partial identifiers can be verified based upon the bloom filterinformation in check B. Hence, if two non-matching partial identifiersare combined at the receiving wireless terminal and evaluated through abloom filter, the resultant derived information can differ from thebloom filter information included in the check B (e.g., to determinethat such a combination of partial identifiers is incorrect). Moreover,it is to be appreciated that a combination of any number of partialidentifiers can be evaluated with a particular bloom filter check tolink the partial identifiers signaled during differing peer discoveryintervals, and the claimed subject matter is not limited to checking twopartial identifiers as described above. Pursuant to anotherillustration, the bloom filter check information can be signaled with asubset of the partial identifiers as opposed to with each partialidentifier as shown.

The following provides an additional example; however, it iscontemplated that the claimed subject matter is not so limited. A peerdiscovery slot can be divided into two halves. In the first half,wireless terminals can advertise a portion of their ID by transmittingon the corresponding time-frequency square. Between peer discovery slotsthere can be a certain amount of overlap in the ID portions advertised.By looking at several peer discovery slots, wireless terminals can linktogether the ID portions of their peers. The second half of the slot canhave a particular structure that can assist in the linkage procedure.Also, overlapped sections of the ID portions can also assist in thelinkage procedure.

Each wireless terminal can take its 32 bit ID and append 8 parity checksto an end to form a 40 bit coded ID. The coded ID can be denoted x=[x₀,. . . , x₃₉]. In discovery slot t, each wireless terminal can form a 10bit segment of its ID: y_(t)=[x_(5tmod39),x_(5t+1mod39), . . . ,x_(5t+9mod39)]. Note that segments y_(t) and y_(t+1) overlap by 5 bitsand that y_(t) is periodic in t. Denote z_(t)=[x_(5tmod39),x_(5t+1mod39), . . . , x_(5t+14mod39)].

The peer discovery slot can be divided into two halves: A and B. Thefirst half can be further subdivided into two sections: A1 and A2. Insections A1 and A2, there can be 64×16=1024 time-frequency squares. Thetime-frequency squares of section A1 can be associated with a randompermutation of the integers {0, . . . , 1023}. The time-frequencysquares of section A2 can be associated with a different randompermutation of the integers {0, . . . , 1023 }.

During the A half of the discovery slot t, each wireless terminaltransmits once in section A1 and once in section A2, each time on thetime-frequency square corresponding to its 10 bit ID segment, y_(t).Note that these squares tend to be different (with high probability).

The B half of the discovery slot can include 64×32=2048 time-frequencysquares. Each 15 bit ID segment can be associated with a random 5 squaresubset of the 2048 squares. Note that there are 2048 choose 5 suchsubsets and 220 possible 20 bit ID segments. During the B half ofdiscovery slot t, each wireless terminal can transmit on the 5time-frequency squares of the subset associated with its 15 bit IDsegment z_(t).

To decode the IDs of its peers, a receiving wireless terminal can make alist of all 10 bit ID segments observed in either the A1 section or theA2 section of the first discovery slot it listens to. Further, thereceiving wireless terminal can form a similar list for the seconddiscovery slot. Then, the receiving wireless terminal can attempt tolink the two collections of 10 bit IDs. For example, the receivingwireless terminal can look for pairs of IDs for which the last 5 bits ofthe first ID match the first 5 bits of the second ID. Once a match islocated, a check can be performed upon the associated 5 time-frequencysquares in the B section of the second discovery window. If all 5squares are received with sufficient power, the associated 15 bit ID canbe written into a concatenation list. If one or more of the 5 squares inthe B section are not received with sufficient power, the 15 bit ID canbe discarded. For those squares that cannot be checked due to thewireless terminal simultaneously transmitting during that symbol time,the wireless terminal can assume the transmission took place. Once twoID segments have been linked, the wireless terminal can proceed to athird discovery slot. The wireless terminal can create a list of all 10bit ID segments observed in either the A1 or the A2 sections. For those10 bit ID segments whose last 5 bits overlap with the last five bits ofone of the ID on the concatenation list, the mobile checks the B sectionof the current discovery slot. If the 5 time frequency squaresassociated with the 15 bit ID are all checked, the wireless terminal canextend the 15 bit ID to a 20 bit ID by adding the last 5 bits of thecurrent segment. The wireless terminal can then proceed to the fourthwindow, and so forth, until the IDs in the concatenation list are 40bits long (or any length associated with a coded ID utilized inconnection therewith). At this point, the wireless terminal can checkthe 8 parity bits of the 40 bit ID on the concatenation list. If allparity checks pass, the 32 bit ID can be written into a peer discoverylist. Then, the discovery procedure can restart again to add additionalIDs to the peer discovery list, and so forth.

With reference to FIG. 15, illustrated is an example graphical depiction1500 of a sliding window and a bloom filter. A time-frequency squarecorresponding to the 10 bit ID segment yt can be included in eachsection A1 and A2. Additionally, a subset of time-frequency squarescorresponding to a 15 bit ID segment z_(t) can be included in section B.The A half can be referred to as the sliding window component of thediscovery slot as peers use it to advertise a segment of their IDcorresponding to a sliding window. The B half can be referred to as thebloom filter component as this can implement the bloom filter operation.Both the sliding window and the bloom filter can be used to link the 10bit ID segments. The 8 parity check bits can be used to reduce the falsealarm rate. The reason the sliding window component can be repeated intwo halves, A1 and A2, is for frequency diversity. When the channel isfrequency selective and the tone of one of the sliding windowtransmissions of a particular peer falls into a null, the entire sevendiscovery slots can be wasted (for the purpose of learning the full IDof that peer).

Referring to FIGS. 16-23, methodologies relating to performing peerdiscovery within a peer-to-peer network are illustrated. While, forpurposes of simplicity of explanation, the methodologies are shown anddescribed as a series of acts, it is to be understood and appreciatedthat the methodologies are not limited by the order of acts, as someacts may, in accordance with one or more embodiments, occur in differentorders and/or concurrently with other acts from that shown and describedherein. For example, those skilled in the art will understand andappreciate that a methodology could alternatively be represented as aseries of interrelated states or events, such as in a state diagram.Moreover, not all illustrated acts may be required to implement amethodology in accordance with one or more embodiments.

Turning to FIG. 16, illustrated is a methodology 1600 that facilitatesdirectly signaling an identifier during peer discovery. At 1602, a timevarying coded identifier can be generated. For example, a transmittingwireless terminal can be associated with a 32 bit identifier. Moreover,an additional 13 bits that can vary with time (or a portion of which canbe time varying) can be added to the original 32 bit identifier to yielda 45 bit coded identifier. However, it is contemplated that the claimedsubject matter is not so limited. Further, for instance, the codedidentifier can be partitioned into seven 6 bit groups and one 3 bitgroup. At 1604, a segment from a plurality of segments with a peerdiscovery resource can be selected based upon a portion of the codedidentifier. According to an illustration, the resource can be 64 tonesby 64 symbols. Further, the resource can be partitioned into 8 segments,each of which can include 8 symbols (e.g., and the corresponding tones).For example, the segment can be selected based upon the 3 bit groupincluded in the coded identifier; therefore, the segment selected cansignal the 3 bit group of the coded identifier. Moreover, the selectedsegment can vary during differing peer discovery intervals; thus,colliding wireless terminals that transmit concurrently during a peerdiscovery interval can obtain identifiers of each other during asubsequent peer discovery interval (e.g., due to the half duplex natureof peer discovery where a wireless terminal either transmits or receivesat a particular time). At 1606, the remainder of the coded identifiercan be signaled during the selected segment. For example, seven tonescan be transmitted during the selected segment, where each tone can besignaled upon a disparate symbol within such segment; thus, each tonecan provide 6 bits of the identifier thereby enabling communication ofthe seven 6 bit groups of the coded identifier. Additionally, the eighthsymbol in the segment can be a reserved (e.g., unused) symbol.

Now turning to FIG. 17, illustrated is a methodology 1700 thatfacilitates decoding a directly signaled identifier during peerdiscovery. At 1702, tones can be received upon symbols in a segment of apeer discovery resource. For example, the segment can include 8 symbols,and the resource can include 8 segments; yet, the claimed subject matteris not so limited. It is contemplated that any number of tones can beobtained upon each of the symbols. At 1704, a particular tone from eachof the symbols can be correlated based upon power level similarity todetermine a sequence of tones obtained from a common transmittingwireless terminal. For example, the highest energy tone upon each of thesymbols in the segment can form the sequence. Moreover, any tone with asubstantially different energy level can be removed from the sequence asenergy levels of tones from a common source tend to be similar (e.g.,since a transmitting wireless terminal sends the tones at asubstantially similar energy level). It is contemplated that any numberof sequences can be formed from within the segment, and each of thesesequences can yield a disparate peer identifier. At 1706, an identifierof the transmitting wireless terminal can be determined based upon thesegment and the sequence of tones. For example, identity of the segmentout of a set of segments within the peer discovery resource can bedecoded to yield a portion of the identifier. Moreover, the tones in thesequence can be decoded to obtain the remainder of the identifier.Additionally, parity checks upon the coded identifier can be performedand, if successful, a raw identifier corresponding to the codedidentifier can be added to a peer list.

Referring to FIG. 18, illustrated is a methodology 1800 that facilitatesincorporating reserved symbols within a peer discovery interval. At1802, timing within a peer to peer network can be synchronized. Forexample, a transmitting wireless terminal and a receiving wirelessterminal can synchronize operation (e.g., based upon a common clockreference); however, offset can exist between timing of these wirelessterminals. At 1804, at least a portion of an identifier can betransmitted during a peer discovery interval as specified by the timing(e.g., of the transmitting wireless terminal). For example, a codedidentifier can be generated by including time varying bits therein.Moreover, it is contemplated that the identifier can be signaled in anymanner (e.g., utilizing direct signaling, transfer partial identifierswith overlap and/or that employ bloom filter information, . . . ). At1806, at least one symbol within the peer discovery interval can bereserved to enable identifying and recovering from timing offset. Thereserved symbol can be an unused (e.g., null) symbol. According to anexample, one symbol within a segment (e.g., a last symbol in eachsegment) can be reserved for direct signaling.

Turning to FIG. 19, illustrated is a methodology 1900 that facilitatesshifting timing to mitigate offset within peer discovery. At 1902,timing within a peer to peer network can be synchronized. At 1904, tonescan be received upon symbols pertaining to at least one identifierduring a peer discovery interval. At 1906, timing offset can beidentified upon obtaining a tone upon a reserved symbol. For example, ifa tone is obtained during a time associated with the reserved symbol,offset can be recognized. At 1908, the timing offset can be corrected.For example, the timing of the received tones can be shifted to align areceived null with an expected null associated with the reserved symbol.

With reference to FIG. 20, illustrated is a methodology 2000 thatfacilitates signaling an identifier over a plurality of peer discoveryintervals. At 2002, a first partial identifier can be transmitted duringa first peer discovery interval. For example, an uncoded identifier caninclude 32 bits, and 8 parity bits can be added thereto to form a 40 bitcoded identifier. However, it is contemplated that any size identifier(or plurality of identifiers) can be utilized in connection with theclaimed subject matter. Moreover, the first partial identifier caninclude a first Y bits of the identifier (e.g., coded identifier, . . .), where Y can be any integer. According to an example, Y can be 10;yet, the claimed subject matter is not so limited. At 2004, a secondpartial identifier can be transmitted during a second peer discoveryinterval where X bits overlap within the first partial identifier andthe second partial identifier. Further, X can be any integer less thanor equal to Y. Moreover, the second partial identifier can comprise Ybits (e.g., 10 bits) in total including the X (e.g., 5) overlappingbits. Additionally, the overlapping bits can enable a receiving wirelessterminal to link the first partial identifier and the second partialidentifier together.

Referring now to FIG. 21, illustrated is a methodology 2100 thatfacilitates linking partial identifiers obtained during differing peerdiscovery intervals based upon overlapping information. At 2102, a firstset of partial identifiers can be received during a first peer discoveryinterval. At 2104, a second set of partial identifiers can be receivedduring a second peer discovery interval. For example, the first peerdiscovery interval and the second peer discovery interval can beadjacent peer discovery intervals. Moreover, it is contemplated that anynumber of partial identifiers can be included in the first set and thesecond set, and the sets can be of equal or differing size. At 2106,partial identifiers from the first set and the second set can be matchedbased upon bit overlap. For example, a last X bits of a partialidentifier in the first set can match a first X bits of a partialidentifier in the second set; hence, these partial identifiers can belinked to one another. Moreover, any number of additional sets ofpartial identifiers can be similarly received and linked to yieldcomplete identifiers of peers.

Now turning to FIG. 22, illustrated is a methodology 2200 thatfacilitates employing a bloom filter while signaling partial identifiersfor peer discovery. At 2202, a first partial identifier can betransmitted during a first peer discovery interval. At 2204, a secondpartial identifier can be transmitted during a second peer discoveryinterval. For example, the first partial identifier can include a firstY bits of an identifier, the second partial identifier can include anext Y bits of the identifier, and so forth, where Y can be any integer(e.g., Y can be 10). According to another illustration, the partialidentifiers can overlap one another (e.g., X bits can overlap betweenpartial identifiers communicated during adjacent peer discoveryintervals). At 2206, bloom filter information can be generated basedupon the combination of the first partial identifier and the secondpartial identifier. For example, the combination of the partialidentifiers can be input to the bloom filter to yield the bloom filterinformation. At 2208, the bloom filter information can be transmitted toenable a peer to link the first partial identifier and the secondpartial identifier. For example, the bloom filter information can betransmitted during the second peer discovery interval along with thesecond partial identifier; however, the claimed subject matter is not solimited. Moreover, the aforementioned can be repeated for additionalpartial identifiers to communicate the entirety of the identifier.

Referring to FIG. 23, illustrated is a methodology 2300 that facilitatesemploying a bloom filter to match partial identifiers. At 2302, a firstset of partial identifiers can be received during a first peer discoveryinterval. At 2304, a second set of partial identifiers can be receivedduring a second peer discovery interval. It is contemplated that anynumber of partial identifiers can be received during the first peerdiscovery interval and/or the second peer discovery interval. At 2306,partial identifiers from the first set and the second set can be linkedbased upon received bloom filter information. For example, an identifierfrom the first set and an identifier from the second set can be combinedand inputted to a bloom filter at the receiving wireless terminal, andthe resultant information can be compared to the received bloom filterinformation. If the resultant information exists within the receivedbloom filter information, then a link is identified between suchidentifiers.

It will be appreciated that, in accordance with one or more aspectsdescribed herein, inferences can be made regarding discovering andidentifying peers in a peer-to-peer environment. As used herein, theterm to “infer” or “inference” refers generally to the process ofreasoning about or inferring states of the system, environment, and/oruser from a set of observations as captured via events and/or data.Inference can be employed to identify a specific context or action, orcan generate a probability distribution over states, for example. Theinference can be probabilistic—that is, the computation of a probabilitydistribution over states of interest based on a consideration of dataand events. Inference can also refer to techniques employed forcomposing higher-level events from a set of events and/or data. Suchinference results in the construction of new events or actions from aset of observed events and/or stored event data, whether or not theevents are correlated in close temporal proximity, and whether theevents and data come from one or several event and data sources.

According to an example, one or more methods presented above can includemaking inferences pertaining to synchronizing a peer discovery intervalfor utilization in connection with communicating via the peer-to-peernetwork. In accordance with another example, an inference may be maderelated to estimating a common notion of time from a broadcast signal inthe peer-to-peer network. It will be appreciated that the foregoingexamples are illustrative in nature and are not intended to limit thenumber of inferences that can be made or the manner in which suchinferences are made in conjunction with the various embodiments and/ormethods described herein.

FIG. 24 depicts an example communication system 2400 implemented inaccordance with various aspects including multiple cells: cell I 2402,cell M 2404. Note that neighboring cells 2402, 2404 overlap slightly, asindicated by cell boundary region 2468. Each cell 2402, 2404 of system2400 includes three sectors. Cells which have not been subdivided intomultiple sectors (N=1), cells with two sectors (N=2) and cells with morethan 3 sectors (N>3) are also possible in accordance with variousaspects. Cell 2402 includes a first sector, sector I 2410, a secondsector, sector II 2412, and a third sector, sector III 2414. Each sector2410, 2412, 2414 has two sector boundary regions; each boundary regionis shared between two adjacent sectors.

Cell I 2402 includes a base station (BS), base station I 2406, and aplurality of end nodes (ENs) (e.g., wireless terminals) in each sector2410, 2412, 2414. Sector I 2410 includes EN(1) 2436 and EN(X) 2438;sector II 2412 includes EN(1′) 2444 and EN(X′) 2446; sector III 2414includes EN(1″) 2452 and EN(X″) 2454. Similarly, cell M 2404 includesbase station M 2408, and a plurality of end nodes (ENs) in each sector2422, 2424, 2426. Sector I 2422 includes EN(1) 2436′ and EN(X) 2438′;sector II 2424 includes EN(1′) 2444′ and EN(X′) 2446′; sector 3 2426includes EN(1″) 2452′ and EN(X″) 2454′.

System 2400 also includes a network node 2460 which is coupled to BS I2406 and BS M 2408 via network links 2462, 2464, respectively. Networknode 2460 is also coupled to other network nodes, e.g., other basestations, AAA server nodes, intermediate nodes, routers, etc. and theInternet via network link 2466. Network links 2462, 2464, 2466 may be,e.g., fiber optic cables. Each end node, e.g., EN(1) 2436 may be awireless terminal including a transmitter as well as a receiver. Thewireless terminals, e.g., EN(1) 2436 may move through system 2400 andmay communicate via wireless links with the base station in the cell inwhich the EN is currently located. The wireless terminals, (WTs), e.g.,EN(1) 2436, may communicate with peer nodes, e.g., other WTs in system2400 or outside system 2400 via a base station, e.g., BS 2406, and/ornetwork node 2460. WTs, e.g., EN(1) 2436 may be mobile communicationsdevices such as cell phones, personal data assistants with wirelessmodems, etc.

Local area peer-to-peer communication may also be supported bycommunication system 2400. For example, a common spectrum may beutilized for both local area peer-to-peer communication as well ascommunication via the wide area network (e.g., cellular infrastructurenetwork). Wireless terminals may communicate with other peers via alocal area peer-to-peer network such as peer-to-peer networks 2470,2472, and 2474. Although three peer-to-peer networks 2470-2474 aredepicted, it is to be appreciated that any number, size, shape, etc. ofpeer-to-peer networks may be supported. For instance, each peer-to-peernetwork 2470-2474 may support transfer of signals directly betweenwireless terminals. Further, each peer-to-peer network 2470-2474 mayinclude wireless terminals within a similar geographic area (e.g.,within range of one another). For example, EN(1) 2436 may communicatewith EN(X) 2438 by way of the local area peer-to-peer network 2470.However, it is to be appreciated that wireless terminals need not beassociated with the same sector and/or cell to be included in a commonpeer-to-peer network. Further, peer-to-peer networks may overlap (e.g.,EN(X′) 2446 may leverage peer-to-peer networks 2472 and 2474).Additionally, some wireless terminals may not be supported by apeer-to-peer network. Wireless terminals may employ the wide areanetwork and/or the peer-to-peer network where such networks overlap(e.g., concurrently or serially). Moreover, wireless terminals mayseamlessly switch or concurrently leverage such networks. Accordingly,wireless terminals whether transmitting and/or receiving may selectivelyemploy one or more of the networks to optimize communications.

FIG. 25 illustrates an example base station 2500 in accordance withvarious aspects. Base station 2500 implements tone subset allocationsequences, with different tone subset allocation sequences generated forrespective different sector types of the cell. Base station 2500 may beused as any one of base stations 2406, 2408 of the system 2400 of FIG.24. The base station 2500 includes a receiver 2502, a transmitter 2504,a processor 2506, e.g., CPU, an input/output interface 2508 and memory2510 coupled together by a bus 2509 over which various elements 2502,2504, 2506, 2508, and 2510 may interchange data and information.

Sectorized antenna 2503 coupled to receiver 2502 is used for receivingdata and other signals, e.g., channel reports, from wireless terminalstransmissions from each sector within the base station's cell.Sectorized antenna 2505 coupled to transmitter 2504 is used fortransmitting data and other signals, e.g., control signals, pilotsignal, beacon signals, etc. to wireless terminals 2600 (see FIG. 26)within each sector of the base station's cell. In various aspects, basestation 2500 may employ multiple receivers 2502 and multipletransmitters 2504, e.g., an individual receiver 2502 for each sector andan individual transmitter 2504 for each sector. Processor 2506, may be,e.g., a general purpose central processing unit (CPU). Processor 2506controls operation of base station 2500 under direction of one or moreroutines 2518 stored in memory 2510 and implements the methods. I/Ointerface 2508 provides a connection to other network nodes, couplingthe BS 2500 to other base stations, access routers, AAA server nodes,etc., other networks, and the Internet. Memory 2510 includes routines2518 and data/information 2520.

Data/information 2520 includes data 2536, tone subset allocationsequence information 2538 including downlink strip-symbol timeinformation 2540 and downlink tone information 2542, and wirelessterminal (WT) data/info 2544 including a plurality of sets of WTinformation: WT 1 info 2546 and WT N info 2560. Each set of WT info,e.g., WT 1 info 2546 includes data 2548, terminal ID 2550, sector ID2552, uplink channel information 2554, downlink channel information2556, and mode information 2558.

Routines 2518 include communications routines 2522 and base stationcontrol routines 2524. Base station control routines 2524 includes ascheduler module 2526 and signaling routines 2528 including a tonesubset allocation routine 2530 for strip-symbol periods, other downlinktone allocation hopping routine 2532 for the rest of symbol periods,e.g., non strip-symbol periods, and a beacon routine 2534.

Data 2536 includes data to be transmitted that will be sent to encoder2514 of transmitter 2504 for encoding prior to transmission to WTs, andreceived data from WTs that has been processed through decoder 2512 ofreceiver 2502 following reception. Downlink strip-symbol timeinformation 2540 includes the frame synchronization structureinformation, such as the superslot, beaconslot, and ultraslot structureinformation and information specifying whether a given symbol period isa strip-symbol period, and if so, the index of the strip-symbol periodand whether the strip-symbol is a resetting point to truncate the tonesubset allocation sequence used by the base station. Downlink toneinformation 2542 includes information including a carrier frequencyassigned to the base station 2500, the number and frequency of tones,and the set of tone subsets to be allocated to the strip-symbol periods,and other cell and sector specific values such as slope, slope index andsector type.

Data 2548 may include data that WT1 2600 has received from a peer node,data that WT 1 2600 desires to be transmitted to a peer node, anddownlink channel quality report feedback information. Terminal ID 2550is a base station 2500 assigned ID that identifies WT 1 2600. Sector ID2552 includes information identifying the sector in which WT1 2600 isoperating. Sector ID 2552 can be used, for example, to determine thesector type. Uplink channel information 2554 includes informationidentifying channel segments that have been allocated by scheduler 2526for WT1 2600 to use, e.g., uplink traffic channel segments for data,dedicated uplink control channels for requests, power control, timingcontrol, etc. Each uplink channel assigned to WT 1 2600 includes one ormore logical tones, each logical tone following an uplink hoppingsequence. Downlink channel information 2556 includes informationidentifying channel segments that have been allocated by scheduler 2526to carry data and/or information to WT1 2600, e.g., downlink trafficchannel segments for user data. Each downlink channel assigned to WT12600 includes one or more logical tones, each following a downlinkhopping sequence. Mode information 2558 includes information identifyingthe state of operation of WT1 2600, e.g. sleep, hold, on.

Communications routines 2522 control the base station 2500 to performvarious communications operations and implement various communicationsprotocols. Base station control routines 2524 are used to control thebase station 2500 to perform basic base station functional tasks, e.g.,signal generation and reception, scheduling, and to implement the stepsof the method of some aspects including transmitting signals to wirelessterminals using the tone subset allocation sequences during thestrip-symbol periods.

Signaling routine 2528 controls the operation of receiver 2502 with itsdecoder 2512 and transmitter 2504 with its encoder 2514. The signalingroutine 2528 is responsible for controlling the generation oftransmitted data 2536 and control information. Tone subset allocationroutine 2530 constructs the tone subset to be used in a strip-symbolperiod using the method of the aspect and using data/information 2520including downlink strip-symbol time info 2540 and sector ID 2552. Thedownlink tone subset allocation sequences will be different for eachsector type in a cell and different for adjacent cells. The WTs 2600receive the signals in the strip-symbol periods in accordance with thedownlink tone subset allocation sequences; the base station 2500 usesthe same downlink tone subset allocation sequences in order to generatethe transmitted signals. Other downlink tone allocation hopping routine2532 constructs downlink tone hopping sequences, using informationincluding downlink tone information 2542, and downlink channelinformation 2556, for the symbol periods other than the strip-symbolperiods. The downlink data tone hopping sequences are synchronizedacross the sectors of a cell. Beacon routine 2534 controls thetransmission of a beacon signal, e.g., a signal of relatively high powersignal concentrated on one or a few tones, which may be used forsynchronization purposes, e.g., to synchronize the frame timingstructure of the downlink signal and therefore the tone subsetallocation sequence with respect to an ultra-slot boundary.

FIG. 26 illustrates an example wireless terminal (e.g., end node, mobiledevice, . . . ) 2600 which can be used as any one of the wirelessterminals (e.g., end nodes, mobile devices, . . . ), e.g., EN(1) 2436,of the system 2400 shown in FIG. 24. Wireless terminal 2600 implementsthe tone subset allocation sequences. Wireless terminal 2600 includes areceiver 2602 including a decoder 2612, a transmitter 2604 including anencoder 2614, a processor 2606, and memory 2608 which are coupledtogether by a bus 2610 over which the various elements 2602, 2604, 2606,2608 can interchange data and information. An antenna 2603 used forreceiving signals from a base station 2500 (and/or a disparate wirelessterminal) is coupled to receiver 2602. An antenna 2605 used fortransmitting signals, e.g., to base station 2500 (and/or a disparatewireless terminal) is coupled to transmitter 2604.

The processor 2606 (e.g., a CPU) controls operation of wireless terminal2600 and implements methods by executing routines 2620 and usingdata/information 2622 in memory 2608.

Data/information 2622 includes user data 2634, user information 2636,tone subset allocation sequence information 2650, and a buddy peer list2656. User data 2634 may include data, intended for a peer node, whichwill be routed to encoder 2614 for encoding prior to transmission bytransmitter 2604 to base station 2500, and data received from the basestation 2500 which has been processed by the decoder 2612 in receiver2602. User information 2636 includes uplink channel information 2638,downlink channel information 2640, terminal ID information 2642, basestation ID information 2644, sector ID information 2646, and modeinformation 2648. Uplink channel information 2638 includes informationidentifying uplink channels segments that have been assigned by basestation 2500 for wireless terminal 2600 to use when transmitting to thebase station 2500. Uplink channels may include uplink traffic channels,dedicated uplink control channels, e.g., request channels, power controlchannels and timing control channels. Each uplink channel includes oneor more logic tones, each logical tone following an uplink tone hoppingsequence. The uplink hopping sequences are different between each sectortype of a cell and between adjacent cells. Downlink channel information2640 includes information identifying downlink channel segments thathave been assigned by base station 2500 to WT 2600 for use when BS 2500is transmitting data/information to WT 2600. Downlink channels mayinclude downlink traffic channels and assignment channels, each downlinkchannel including one or more logical tone, each logical tone followinga downlink hopping sequence, which is synchronized between each sectorof the cell.

User info 2636 also includes terminal ID information 2642, which is abase station 2500 assigned identification, base station ID information2644 which identifies the specific base station 2500 that WT hasestablished communications with, and sector ID info 2646 whichidentifies the specific sector of the cell where WT 2500 is presentlylocated. Base station ID 2644 provides a cell slope value and sector IDinfo 2646 provides a sector index type; the cell slope value and sectorindex type may be used to derive tone hopping sequences. Modeinformation 2648 also included in user info 2636 identifies whether theWT 2600 is in sleep mode, hold mode, or on mode.

Tone subset allocation sequence information 2650 includes downlinkstrip-symbol time information 2652 and downlink tone information 2654.Downlink strip-symbol time information 2652 include the framesynchronization structure information, such as the superslot,beaconslot, and ultraslot structure information and informationspecifying whether a given symbol period is a strip-symbol period, andif so, the index of the strip-symbol period and whether the strip-symbolis a resetting point to truncate the tone subset allocation sequenceused by the base station. Downlink tone info 2654 includes informationincluding a carrier frequency assigned to the base station 2500, thenumber and frequency of tones, and the set of tone subsets to beallocated to the strip-symbol periods, and other cell and sectorspecific values such as slope, slope index and sector type.

Routines 2620 include communications routines 2624, wireless terminalcontrol routines 2626, synchronization routines 2628, paging messagegeneration/broadcast routines 2630, and paging message detectionroutines 2632. Communications routines 2624 control the variouscommunications protocols used by WT 2600. For example, communicationsroutines 2624 may enable communicating via a wide area network (e.g.,with base station 2500) and/or a local area peer-to-peer network (e.g.,directly with disparate wireless terminal(s)). By way of furtherexample, communications routines 2624 may enable receiving a broadcastsignal (e.g., from base station 2500). Wireless terminal controlroutines 2626 control basic wireless terminal 2600 functionalityincluding the control of the receiver 2602 and transmitter 2604.Synchronization routines 2628 control synchronizing wireless terminal2600 to a received signal (e.g., from base station 2500). Peers within apeer-to-peer network may also be synchronized to the signal. Forexample, the received signal may be a Beacon, a PN (pseudo random)sequence signal, a pilot signal, etc. Further, the signal may beperiodically obtained and a protocol (e.g., associated withsynchronization routines 2628) also known to peers may be utilized toidentify intervals corresponding to distinct functions (e.g., peerdiscovery, paging, traffic). Paging message generation/broadcastroutines 2630 control creating a message for transmission during anidentified peer paging interval. A symbol and/or tone associated withthe message may be selected based upon a protocol (e.g., associated withpaging message generation/broadcast routines 2630). Moreover, pagingmessage generation/broadcast routines 2630 may control sending themessage to peers within the peer-to-peer network. Paging messagedetection routines 2632 control detection and identification of peersbased upon messages received during an identified peer paging interval.Further, paging message detection routines 2632 may identify peers basedat least in part upon information retained in buddy peer list 2656.

With reference to FIG. 27, illustrated is a system 2700 that enablesdirectly signaling an identifier during peer discovery. For example,system 2700 may reside at least partially within a wireless terminal. Itis to be appreciated that system 2700 is represented as includingfunctional blocks, which may be functional blocks that representfunctions implemented by a processor, software, or combination thereof(e.g., firmware). System 2700 includes a logical grouping 2702 ofelectrical components that can act in conjunction. For instance, logicalgrouping 2702 may include an electrical component for generating a timevarying coded identifier 2704. Further, logical grouping 2702 maycomprise an electrical component for selecting a segment from aplurality of segments within a peer discovery resource for transmissionbased upon a portion of the coded identifier 2706. Moreover, logicalgrouping 2702 may include an electrical component for signaling aremainder of the coded identifier during the selected segment 2708.Additionally, system 2700 may include a memory 2710 that retainsinstructions for executing functions associated with electricalcomponents 2704, 2706, and 2708. While shown as being external to memory2710, it is to be understood that one or more of electrical components2704, 2706, and 2708 may exist within memory 2710.

With reference to FIG. 28, illustrated is a system 2800 that enablesdecoding a directly signaled identifier during peer discovery. Forexample, system 2800 may reside at least partially within a wirelessterminal. It is to be appreciated that system 2800 is represented asincluding functional blocks, which may be functional blocks thatrepresent functions implemented by a processor, software, or combinationthereof (e.g., firmware). System 2800 includes a logical grouping 2802of electrical components that can act in conjunction. For instance,logical grouping 2802 may include an electrical component for receivingtones upon symbols in a segment of a peer discovery resource 2804.Further, logical grouping 2802 may comprise an electrical component forcorrelating a particular tone from each of the symbols based upon powerlevel similarity to determine a sequence of tones obtained from a commontransmitting wireless terminal 2806. Moreover, logical grouping 2802 mayinclude an electrical component for determining an identifier of thetransmitting wireless terminal based upon the segment and the sequenceof tones 2808. Additionally, system 2800 may include a memory 2810 thatretains instructions for executing functions associated with electricalcomponents 2804, 2806, and 2808. While shown as being external to memory2810, it is to be understood that one or more of electrical components2804, 2806, and 2808 may exist within memory 2810.

With reference to FIG. 29, illustrated is a system 2900 that enablesincorporating reserved symbols within a peer discovery interval. Forexample, system 2900 may reside at least partially within a wirelessterminal. It is to be appreciated that system 2900 is represented asincluding functional blocks, which may be functional blocks thatrepresent functions implemented by a processor, software, or combinationthereof (e.g., firmware). System 2900 includes a logical grouping 2902of electrical components that can act in conjunction. For instance,logical grouping 2902 may include an electrical component forsynchronizing timing within a peer to peer network 2904. Further,logical grouping 2902 may comprise an electrical component fortransmitting at least a portion of an identifier during a peer discoveryinterval as specified by the timing 2906. Moreover, logical grouping2902 may include an electrical component for reserving at least onesymbol within the peer discovery interval to enable identifying andrecovering from timing offset 2908. Additionally, system 2900 mayinclude a memory 2910 that retains instructions for executing functionsassociated with electrical components 2904, 2906, and 2908. While shownas being external to memory 2910, it is to be understood that one ormore of electrical components 2904, 2906, and 2908 may exist withinmemory 2910.

With reference to FIG. 30, illustrated is a system 3000 that enablesshifting timing to mitigate offset within peer discovery. For example,system 3000 may reside at least partially within a wireless terminal. Itis to be appreciated that system 3000 is represented as includingfunctional blocks, which may be functional blocks that representfunctions implemented by a processor, software, or combination thereof(e.g., firmware). System 3000 includes a logical grouping 3002 ofelectrical components that can act in conjunction. For instance, logicalgrouping 3002 may include an electrical component for synchronizingtiming within a peer to peer network 3004. Further, logical grouping3002 may comprise an electrical component for receiving tones uponsymbols pertaining to at least one identifier during a peer discoveryinterval 3006. Moreover, logical grouping 3002 may include an electricalcomponent for identifying timing offset upon obtaining a tone upon areserved symbol 3008. Logical grouping 3002 may also include anelectrical component for correcting the timing offset 3010.Additionally, system 3000 may include a memory 3012 that retainsinstructions for executing functions associated with electricalcomponents 3004, 3006, 3008, and 3010. While shown as being external tomemory 3012, it is to be understood that one or more of electricalcomponents 3004, 3006, 3008, and 3010 may exist within memory 3012.

With reference to FIG. 31, illustrated is a system 3100 that enablessignaling an identifier over a plurality of peer discovery intervals.For example, system 3100 may reside at least partially within a wirelessterminal. It is to be appreciated that system 3100 is represented asincluding functional blocks, which may be functional blocks thatrepresent functions implemented by a processor, software, or combinationthereof (e.g., firmware). System 3100 includes a logical grouping 3102of electrical components that can act in conjunction. For instance,logical grouping 3102 may include an electrical component fortransmitting a first partial identifier during a peer discovery interval3104. Further, logical grouping 3102 may comprise an electricalcomponent for transmitting a second partial identifier during a secondpeer discovery interval where X bits overlap within the first partialidentifier and the second partial identifier 3106. Additionally, system3100 may include a memory 3108 that retains instructions for executingfunctions associated with electrical components 3104 and 3106. Whileshown as being external to memory 3108, it is to be understood that oneor more of electrical components 3104 and 3106 may exist within memory3108.

With reference to FIG. 32, illustrated is a system 3200 that enableslinking partial identifiers obtained during differing peer discoveryintervals based upon overlapping information. For example, system 3200may reside at least partially within a wireless terminal. It is to beappreciated that system 3200 is represented as including functionalblocks, which may be functional blocks that represent functionsimplemented by a processor, software, or combination thereof (e.g.,firmware). System 3200 includes a logical grouping 3202 of electricalcomponents that can act in conjunction. For instance, logical grouping3202 may include an electrical component for receiving a first set ofpartial identifiers during a first peer discovery interval 3204.Further, logical grouping 3202 may comprise an electrical component forreceiving a second set of partial identifiers during a second peerdiscovery interval 3206. Moreover, logical grouping 3202 may include anelectrical component for matching partial identifiers from the first setand the second set based upon bit overlap 3208. Additionally, system3200 may include a memory 3210 that retains instructions for executingfunctions associated with electrical components 3204, 3206, and 3208.While shown as being external to memory 3210, it is to be understoodthat one or more of electrical components 3204, 3206, and 3208 may existwithin memory 3210.

With reference to FIG. 33, illustrated is a system 3300 that enablesemploying a bloom filter while signaling partial identifiers for peerdiscovery. For example, system 3300 may reside at least partially withina wireless terminal. It is to be appreciated that system 3300 isrepresented as including functional blocks, which may be functionalblocks that represent functions implemented by a processor, software, orcombination thereof (e.g., firmware). System 3300 includes a logicalgrouping 3302 of electrical components that can act in conjunction. Forinstance, logical grouping 3302 may include an electrical component fortransmitting a first partial identifier during a first peer discoveryinterval 3304. Further, logical grouping 3302 may comprise an electricalcomponent for transmitting a second partial identifier during a secondpeer discovery interval 3306. Moreover, logical grouping 3302 mayinclude an electrical component for generating bloom filter informationbased upon the combination of the first partial identifier and thesecond partial identifier 3308. Logical grouping 3302 may also includean electrical component for transmitting the bloom filter information toenable a peer to link the first partial identifier and the secondpartial identifier 3310. Additionally, system 3300 may include a memory3312 that retains instructions for executing functions associated withelectrical components 3304, 3306, 3308, and 3310. While shown as beingexternal to memory 3312, it is to be understood that one or more ofelectrical components 3304, 3306, 3308, and 3310 may exist within memory3312.

With reference to FIG. 34, illustrated is a system 3400 that enablesemploying a bloom filter to match partial identifiers. For example,system 3400 may reside at least partially within a wireless terminal. Itis to be appreciated that system 3400 is represented as includingfunctional blocks, which may be functional blocks that representfunctions implemented by a processor, software, or combination thereof(e.g., firmware). System 3400 includes a logical grouping 3402 ofelectrical components that can act in conjunction. For instance, logicalgrouping 3402 may include an electrical component for receiving a firstset of partial identifiers during a first peer discovery interval 3404.Further, logical grouping 3402 may comprise an electrical component forreceiving a second set of partial identifiers during a second peerdiscovery interval 3406. Moreover, logical grouping 3402 may include anelectrical component for linking partial identifiers from the first setand the second set based upon received bloom filter information 3408.Additionally, system 3400 may include a memory 3410 that retainsinstructions for executing functions associated with electricalcomponents 3404, 3406, and 3408. While shown as being external to memory3410, it is to be understood that one or more of electrical components3404, 3406, and 3408 may exist within memory 3410.

When the embodiments are implemented in software, firmware, middlewareor microcode, program code or code segments, they may be stored in amachine-readable medium, such as a storage component. A code segment mayrepresent a procedure, a function, a subprogram, a program, a routine, asubroutine, a module, a software package, a class, or any combination ofinstructions, data structures, or program statements. A code segment maybe coupled to another code segment or a hardware circuit by passingand/or receiving information, data, arguments, parameters, or memorycontents. Information, arguments, parameters, data, etc. may be passed,forwarded, or transmitted using any suitable means including memorysharing, message passing, token passing, network transmission, etc.

For a software implementation, the techniques described herein may beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The software codes may be storedin memory units and executed by processors. The memory unit may beimplemented within the processor or external to the processor, in whichcase it can be communicatively coupled to the processor via variousmeans as is known in the art.

What has been described above includes examples of one or moreembodiments. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing the aforementioned embodiments, but one of ordinary skill inthe art may recognize that many further combinations and permutations ofvarious embodiments are possible. Accordingly, the described embodimentsare intended to embrace all such alterations, modifications andvariations that fall within the spirit and scope of the appended claims.Furthermore, to the extent that the term “includes” is used in eitherthe detailed description or the claims, such term is intended to beinclusive in a manner similar to the term “comprising” as “comprising”is interpreted when employed as a transitional word in a claim.

1. A method that facilitates incorporating reserved symbols within apeer discovery interval, comprising: synchronizing timing within a peerto peer network; transmitting at least a portion of an identifier duringa peer discovery interval as specified by the timing; and reserving atleast one symbol within the peer discovery interval to enableidentifying and recovering from timing offset.
 2. The method of claim 1,wherein timing of a receiving wireless terminal is offset from thesynchronized timing.
 3. The method of claim 1, wherein the at least onereserved symbol is an unused symbol.
 4. The method of claim 1, whereinthe peer discovery interval includes a plurality of segments and each ofthe segments includes a respective reserved symbol.
 5. The method ofclaim 4, further comprising transmitting the identifier via directsignaling within a selected one of the plurality of segments.
 6. Themethod of claim 5, further comprising transmitting respective tones uponseven symbols in the selected segment as a function of the identifierand reserving an eighth symbol in the selected segment.
 7. A wirelesscommunications apparatus, comprising: a memory that retains instructionsrelated to synchronizing timing within a peer to peer network,transmitting at least a portion of an identifier during a peer discoveryinterval as specified by the timing, and reserving at least one symbolwithin the peer discovery interval to enable identifying and recoveringfrom timing offset; and a processor, coupled to the memory, configuredto execute the instructions retained in the memory.
 8. The wirelesscommunications apparatus of claim 7, wherein timing of a receivingwireless terminal is offset from the synchronized timing.
 9. Thewireless communications apparatus of claim 7, wherein the at least onereserved symbol is an unused symbol.
 10. The wireless communicationsapparatus of claim 7, wherein the peer discovery interval includes aplurality of segments and each of the segments includes a respectivereserved symbol.
 11. The wireless communications apparatus of claim 10,wherein the memory further retains instructions for transmitting theidentifier via direct signaling within a selected one of the pluralityof segments.
 12. The wireless communications apparatus of claim 11,wherein the memory further retains instructions for transmittingrespective tones upon seven symbols in the selected segment as afunction of the identifier and reserving an eighth symbol in theselected segment.
 13. A wireless communications apparatus that enablesincorporating reserved symbols within a peer discovery interval,comprising: means for synchronizing timing within a peer to peernetwork; means for transmitting at least a portion of an identifierduring a peer discovery interval as specified by the timing; and meansfor reserving at least one symbol within the peer discovery interval toenable identifying and recovering from timing offset.
 14. The wirelesscommunications apparatus of claim 13, wherein timing of a receivingwireless terminal is offset from the synchronized timing.
 15. Thewireless communications apparatus of claim 13, wherein the at least onereserved symbol is an unused symbol.
 16. The wireless communicationsapparatus of claim 13, wherein the peer discovery interval includes aplurality of segments and each of the segments includes a respectivereserved symbol.
 17. The wireless communications apparatus of claim 16,further comprising means for transmitting the identifier via directsignaling within a selected one of the plurality of segments.
 18. Thewireless communications apparatus of claim 17, further comprising meansfor transmitting respective tones upon seven symbols in the selectedsegment as a function of the identifier and reserving an eighth symbolin the selected segment.
 19. A machine-readable medium having storedthereon machine-executable instructions for: synchronizing timing withina peer to peer network; transmitting at least a portion of an identifierduring a peer discovery interval as specified by the timing; andreserving at least one symbol within the peer discovery interval toenable identifying and recovering from timing offset.
 20. Themachine-readable medium of claim 19, wherein timing of a receivingwireless terminal is offset from the synchronized timing.
 21. Themachine-readable medium of claim 19, wherein the at least one reservedsymbol is an unused symbol.
 22. The machine-readable medium of claim 19,wherein the peer discovery interval includes a plurality of segments andeach of the segments includes a respective reserved symbol.
 23. Themachine-readable medium of claim 22, the machine-executable instructionsfurther comprise transmitting the identifier via direct signaling withina selected one of the plurality of segments.
 24. The machine-readablemedium of claim 23, the machine-executable instructions further comprisetransmitting respective tones upon seven symbols in the selected segmentas a function of the identifier and reserving an eighth symbol in theselected segment.
 25. In a wireless communication system, an apparatuscomprising: a processor configured to: synchronize timing within a peerto peer network; transmit at least a portion of an identifier during apeer discovery interval as specified by the timing; and reserve at leastone symbol within the peer discovery interval to enable identifying andrecovering from timing offset.
 26. A method that facilitates shiftingtiming to mitigate offset within peer discovery, comprising:synchronizing timing within a peer to peer network; receiving tones uponsymbols pertaining to at least one identifier during a peer discoveryinterval; identifying timing offset upon obtaining a tone upon areserved symbol; and correcting the timing offset.
 27. The method ofclaim 26, further comprising recognizing timing offset upon obtaining atone during a time associated with the reserved symbol.
 28. The methodof claim 26, correcting the timing offset further comprises shiftingtiming of a particular received tone to align a received null with anexpected null associated with the reserved symbol.
 29. The method ofclaim 28, wherein timing of a sequence of received tones is shifted. 30.The method of claim 28, wherein the sequence pertains to a commontransmitting wireless terminal.
 31. The method of claim 26, wherein theat least one identifier is signaled via direct signaling.
 32. The methodof claim 26, wherein partial identifiers are signaled during the peerdiscovery interval and linked with disparate partial identifierssignaled during a disparate peer discovery interval.
 33. A wirelesscommunications apparatus, comprising: a memory that retains instructionsrelated to synchronizing timing within a peer to peer network, receivingtones upon symbols pertaining to at least one identifier during a peerdiscovery interval, identifying timing offset upon obtaining a tone upona reserved symbol, and correcting the timing offset; and a processor,coupled to the memory, configured to execute the instructions retainedin the memory.
 34. The wireless communications apparatus of claim 33,wherein the memory further retains instructions for recognizing timingoffset upon obtaining a tone during a time associated with the reservedsymbol.
 35. The wireless communications apparatus of claim 33, whereinthe memory further retains instructions for correcting the timing offsetfurther comprises shifting timing of a particular received tone to aligna received null with an expected null associated with the reservedsymbol.
 36. The wireless communications apparatus of claim 35, whereintiming of a sequence of received tones is shifted.
 37. The wirelesscommunications apparatus of claim 35, wherein the sequence pertains to acommon transmitting wireless terminal.
 38. The wireless communicationsapparatus of claim 33, wherein the at least one identifier is signaledvia direct signaling.
 39. The wireless communications apparatus of claim33, wherein partial identifiers are signaled during the peer discoveryinterval and linked with disparate partial identifiers signaled during adisparate peer discovery interval.
 40. A wireless communicationsapparatus that enables shifting timing to mitigate offset within peerdiscovery, comprising: means for synchronizing timing within a peer topeer network; means for receiving tones upon symbols pertaining to atleast one identifier during a peer discovery interval; means foridentifying timing offset upon obtaining a tone upon a reserved symbol;and means for correcting the timing offset.
 41. The wirelesscommunications apparatus of claim 40, further comprising means forrecognizing timing offset upon obtaining a tone during a time associatedwith the reserved symbol.
 42. The wireless communications apparatus ofclaim 40, further comprising means for correcting the timing offsetfurther comprises shifting timing of a particular received tone to aligna received null with an expected null associated with the reservedsymbol.
 43. The wireless communications apparatus of claim 42, whereintiming of a sequence of received tones is shifted.
 44. The wirelesscommunications apparatus of claim 42, wherein the sequence pertains to acommon transmitting wireless terminal.
 45. The wireless communicationsapparatus of claim 40, wherein the at least one identifier is signaledvia direct signaling.
 46. The wireless communications apparatus of claim40, wherein partial identifiers are signaled during the peer discoveryinterval and linked with disparate partial identifiers signaled during adisparate peer discovery interval.
 47. A machine-readable medium havingstored thereon machine-executable instructions for: synchronizing timingwithin a peer to peer network; receiving tones upon symbols pertainingto at least one identifier during a peer discovery interval; identifyingtiming offset upon obtaining a tone upon a reserved symbol; andcorrecting the timing offset.
 48. The machine-readable medium of claim47, the machine-executable instructions further comprise recognizingtiming offset upon obtaining a tone during a time associated with thereserved symbol.
 49. The machine-readable medium of claim 47, themachine-executable instructions further comprise correcting the timingoffset further comprises shifting timing of a particular received toneto align a received null with an expected null associated with thereserved symbol.
 50. The machine-readable medium of claim 49, whereintiming of a sequence of received tones is shifted.
 51. Themachine-readable medium of claim 49, wherein the sequence pertains to acommon transmitting wireless terminal.
 52. The machine-readable mediumof claim 47, wherein the at least one identifier is signaled via directsignaling.
 53. The machine-readable medium of claim 47, wherein partialidentifiers are signaled during the peer discovery interval and linkedwith disparate partial identifiers signaled during a disparate peerdiscovery interval.
 54. In a wireless communication system, an apparatuscomprising: a processor configured to: synchronize timing within a peerto peer network; receive tones upon symbols pertaining to at least oneidentifier during a peer discovery interval; identify timing offset uponobtaining a tone upon a reserved symbol; and correct the timing offset.